in his own country which has the disposal of a table in the majority of cases, the application. has to be made to the government. The station lets its tables to scientific corporations or to governments at a yearly rental of four hundred dollars each. There are, at present, twenty tables taken, of which the greater number belong to Austria, Germany, Russia, and Italy. Holland and Belgium have one each, and England has two.

There is room in the station for thirty. The rapid development of the institution is shown by the fact, that, when it was first opened (in January, 1874), only seven tables were taken. About two hundred and thirty biologists among them, very many of the highest eminence have worked in the laboratories of the station in the nine years of its existence; and the published works founded on the studies so carried out form a considerable proportion of the total addition to biological knowledge produced during that period. The brilliant researches of Francis Balfour on the development of elasmobranchs, which formed such a large step in the progress of vertebrate embryology, were carried out chiefly during the time he spent at the table of Cambridge university, in 1874, 1875, and 1877; and he always fully acknowledged the debt he owed to the zoological station and its staff. Professor Grenacher commenced his researches on the eyes of arthropods at the station in 1876, - researches which resulted in his classical work, which is, up to the present, the principal authority on the subject. The brothers Oscar and Richard Hertwig carried out their interesting work on

the histology of the Actiniae at Naples. F. E. Schultze and Oscar Schmidt, two of the principal living spongiologists, have availed themselves of the resources of the station; and Professor Claus, Dr. Hubrecht, Dr. Spengel, and Dr. Chun are other names whose celebrity in zoology is connected with the institution. Last year an American zoologist, Dr. Whitman, carried out some important researches in the Naples laboratory on the curious parasites, Dicyemidae.

The number of those belonging to the permanent scientific staff of the station is eight, including Mr. Petersen, the engineer, to whose skilful and successful management of the machinery the wonderful regularity and efficiency of all the mechanical arrangements is due. The other seven are biologists who are occupied in the preparation of monographs of various classes, for the series published by the station; while they divide among them the work connected with the issue of the two periodical publications, and the routine duties of the laboratories. Dr. Dohrn acts as director, and represents the station to the outside world; while the chief duties of management devolve on Dr. Eisig, to whose devotion and foresight the enterprise owes much of its success. The duties of librarian are discharged by Dr. Brandt, whose name is well known in connection with the recent discoveries that have been made, as to the existence and significance of symbrosis in animals, and who is engaged at present on the monograph of the radiolarians of the gulf. Dr. Lang, in the

course of his work on the turbellarians, has already produced some extremely important papers on their morphology, and the relations of plathelminths generally. The monograph of Dr. Mayer, on the curious crustacean family Caprellidae, has just appeared, and the Copepoda' of Dr. Giesbrecht is rapidly approaching completion. To the two zoologists last named belongs the credit of most of the great improvements in technique which have been invented in the station. The value of these improved methods can scarcely be overestimated. Technical difficulties often stand in

the gulf, and to contain a body of accurate information on the anatomy, histology, classification, and relations of marine forms, which shall serve as a sound basis for future investigations. The series includes Algae as well as animals. They may be written in either of the four generally known European languages. Six have already appeared, the first being the beautiful work of Dr. Chun on the Ctenophorae. One by Dr. Emery has already appeared in Italian; and the Actiniae of Dr. Andres will shortly be published in the same language. They are published by subscription, of which the annual amount is $12.50, and the number of subscribers, up to the present, is two hundred and sixty. The station also issues a journal for original memoirs of work done in its laboratories, called the Mittheilungen aus der zoologischen station,' which commenced in 1879, and whose three volumes contain already much important work; also a bibliography, called the Zoologische jahresbericht,' in which every paper on biological subjects is not only indexed, but summarized. The latter was commenced in 1880.

It will be allowed that the zoological station has already a many-sided activity; that it has done, and is doing, a great deal for biological science; nevertheless, it is about to take a still further expansion. A separate laboratory is in course of preparation for the study of comparative physiology, for which nowhere such favorable conditions could be found as will be provided by the resources of the existing station. Every one who is a friend to the progress of biology must wish the Neapolitan station success in its new enterprise, and a continuance of the successful development which has, up to the present, taken place in the original institution.

EMILY A. NUNN.

THE STATION FISHERMAN.

the way of the solution of definite and important questions: before them the investigator is brought to a stand-still, and his advance in the desired direction hopelessly blocked. The discovery of a rapid and certain method of obtaining series of sections, which science owes to Dr. Giesbrecht, has given a new power to research, and enabled investigations to be undertaken which before were impossible.

The publications of the station have already been mentioned, but it is well to add a few details concerning them. The monographs are intended to form a series of complete studies of every group of animals existing in

EVIDENCES OF GLACIATION IN KENTUCKY.

THE following notes of observations on glacial action south of the Ohio River are submitted to the fund of evidence of glaciation anterior to the period of the great terminal moraine.

1. At the crossing of the Kentucky River by the extension of the Kentucky Central R.R., opposite the mouth of Otter Creek, and in Clark County on the north bank of the river, the following fresh section was obtained at the mouth of the railway-tunnel.

This locality is sixty miles south from the crossing of the Ohio River by the grand moraine.

2. In Rock Castle County, at the summit of the Knoxville branch of the Louisville and Nashville R.R., between Roundstone Lick and Pine Hill, is a hill of modified drift, mainly composed of detritus derived from lower coal conglomerate and limestone. The railway cutting revealed some twelve feet in thickness of this material.

3. At the crossing of Rock Castle River by the same railway, polished and striated blocks of subcarboniferous limestone in situ were seen after removal of the superimposed clays. The striation of these blocks may be due to ice moving down the river, though it is doubtful if river-ice has ever weight enough to do much smoothing and striating work.

4. At the Hazel Patch summit of the same branch railroad, on the highest portion of the Cumberland plateau in Laurel county, a cut of the road revealed a low moraine composed of fragments of carboniferous slates and sandstones, and of the upper coal of this portion of the county. In riding over this plateau two years ago, I encountered this moraine, and then traced it east and west for some distance, suspecting its ice-origin. Subsequent work on the line of the railway confirmed my suspicions.

5. In the summit between Laurel branch of Rock Castle River, and Lynn Camp branch, a heavy bed of glacial clay was encountered, showing the worn-off edges of coal-seams on their northern aspect, and fragments mingled with the clays, similar to coal-beds and clays to be seen almost anywhere in Ohio.

My notes of these two last localities having been mislaid, I cannot describe the sections in detail.

These clay-beds cannot be referred to clays derived from decomposition of shales and marls of the coal strata. The latter are always found in situ, while the glacial clays may repose upon coal, sand-rock, limestone, or any other strata of the county, so that there is no danger of confounding the two. If the recent cuts of railways in construction and of those

lately completed were closely examined, the surface geology of Kentucky would doubtless reveal many other localities where glaciation could be studied to advantage.

R. P. STEVENS.

EARLY DEVELOPMENT OF REPTILES.

W. F. R. WELDON publishes a valuable article on Lacerta muralis (Quart. journ. micr. sc., xxiii. 134). His clearness and conciseness contrast very agreeably with the prolixity of many embryological writings. At the close of segmentation the ectoderm consists of cells very irregularly arranged, often two layers deep. The entoderm is also irregular and two or three cells thick. The area pellucida is formed by the outer cells becoming more columnar, and the inner cells more regular. Soon the posterior end of the area is marked by the presence of the primitive streak, which is a mass of closely packed cells, exhibiting no division into layers. The blastopore commences at the anterior end of this streak as a pit, open above, closed below. The floor of the pit breaks through, and the blastopore assumes its normal condition, forming a communication between the exterior and the primitive entodermic cavity. The mesoderm arises as two lateral outgrowths from the primitive streak, afterwards from the sides of the blastopore, and the axial strip of invaginated hypoblast. Anteriorly the mesoblastic elements are branched cells, which are budded off from the entoderm. (Do not these correspond to Hertwig's mesenchyma?) Weldon confirms Balfour and Stahl's account of the development of the allantois as a process of the primitive streak.

Having examined younger embryos than Braun, Weldon is able to rectify the former's account of the origin of the Wolffian duct and renal tubules. The protovertebrae are connected by an intermediate cellmass with the lateral mesoblast. In this intermediate mass there appears a series of cavities, each opposite a protovertebra, and separate from one another. They are the segmental vesicles described by Rathke and other writers. When twelve protovertebrae are present, the Wolffian duct begins to appear as a solid cord of cells, splitting off from the intermediate cell-mass, and passing, therefore, into the dorso-lateral wall of each segmental vesicle. The duct develops, acquiring a lumen in the intervertebral spaces first; but, when there are fifteen protovertebrae, it becomes a continuous canal through the first eight segments, and acquires at the same time communication with each segmental vesicle. Back of the eighth segment the development is similar, except that the duct grows independently of the vesicles. This agrees with Sedgwick's observations on the process in birds and elasmobranchs.

Another paper on this subject has been published by Dr. H. Strahl (Arch. anat. physiol., anat. abth., 1883, 1). As an introduction, he gives notices of previous researches on the same theme. Then follows a chapter of general remarks, in which the gestation, growth, and gross changes of the embryos, and the manner of obtaining them, are considered. The main part of the article is devoted to a detailed account of the new observations, prefaced by a summary of the results previously obtained by himself. The new part begins with the stage when the blastopore or neurenteric canal is completely formed. The principal new results may be sum marized as follows: in the neurenteric canal, two

parts may be distinguished, one vertical, descending from the blastopore; the other horizontal, running forwards. In the dorsal wall of the latter, the chorda dorsalis makes its first appearance. The canal closes at the same time as the medullary tube. Just before the closure of the blastopore, the 'anlage' of the medullary cord extends around it. After the external closure, the communication between the medullary tube and the digestive cavity is still maintained by the canal. Strahl uses the unfortunate term 'medullary cord' to designate the medullary tube, notochord, and part of the primitive streak together: hence he describes the chorda as being differentiated from the medullary cord. This only adds to the confusion, and is the more to be regretted, since the real origin as described by him agrees with the accounts of other writers, it is at first a modification of the epithelium of the neurenteric canal. The middle portion of the chorda is the first to be grown over by the entoderm: therefore the two ends remain longer uncovered than the middle. At the time when the peripheral mesoderm, forming the area vasculosa, reaches the germ-wall, the latter is already completely fissured. Blood-vessels have begun to appear before this time, and without the participation of the germ-wall. C. S. MINOT.

THE INTERNATIONAL GEOLOGICAL

CONGRESS.

THE compte rendu of the second session of this congress, held at Bologna last year, has just appeared in a thick octavo, with abundant illustrations. The history of the congress, forming the first part of the volume, was prepared by the president, Capellini, and consists of a brief account of its origin with the meeting of the American association for the advancement of science in 1876, a summary of the results of the first meeting at Paris in 1878, a list of the members and officers of the first congress, an account of the choice of Bologna as the rendezvous for the second meeting, of the nomination of the international commissions, of the organization of the second congress, with its rules and regulations, and lists of the members, delegates, and officers. In connection with this latter portion, it is curious to note that a number of the more eminent geologists who originally took part in it no longer belong to the congress; and also that the number of Italians at the congress was 202, although the geological society of Italy has only 120 members, of whom 14 are foreigners.

The second part, prepared by Delaire and Fontannes, besides the proceedings at the different sittings, contains a number of appendices on geological coloring and nomenclature, and one on the classification of mineral masses by M. de Chancourtois, accompanied by a tabular view of lithological synthesis. This author objects to the indiscriminate use of the word 'rock,' and proposes instead the word 'lithe,' which he subdivides, according to the origin of the rock, into analithes, endo-analithes or endolithes, exoanalithes or exolithes, catalithes, peri-catalithes or perilithes, apo-catalithes or apolithes. The reports of the discussion are interesting, as showing the extreme difficulty of reaching any unity in classifications, even on the most trifling points.

The third part (documents of the congress, prepared by the same hands) contains a brief description of the collections and maps exhibited at the congress. Among these may be mentioned the geological map of Italy (scale, 1), engraved in the colors of the international commission, especially for the congress,

1,111,711

in two editions, -one with the mountains figured in hachures, and the other without them. The latter is the clearer, and preferable as a geological map. It is curious that a map on a scale so small should have twelve colors devoted to crystalline rocks, and only ten to the sedimentary strata; and it answers well its purpose as a study of geological map-coloring. The Italian committee also prepared a geological and paleontological bibliography of Italy, containing mention of 6,566 memoirs from the days of Aelianus (693 B.C.) to 1881. Its arrangement is remarkably clear and simple.

The fourth part (annexes) contains in extenso, and in their original language, the reports sent by the national committees to the international commissions established in 1878. They are followed by summaries of a few individual reports on the unification of nomenclature, or of graphic processes.

The scientific communications are the following: 10. Macrographical classification of the trachytes of Hungary, by J. Szabó, already mentioned in SCIENCE. 2o. On the classification of the ancient stratified rocks of the island of Sardinia, by J. G. Bornemann, who has found a number of primordial fossils, paradoxides, etc., with intercalation of the second fauna. This would seem to be analogous to the condition of the Taconic of Vermont. 3°. On the cretaceous system and the great sand-dunes of the northern Sabara, by G. Roland. He considers the cretaceous as consisting of the middle and upper divisions; that the sand-dunes constitute distinct chains, formed entirely by the wind, and depending for their orography on topographical accidents; that the larger dunes are not moved by the action of the wind, the position of the masses, and the orography of the chains, varying but little, excepting that, as a mass, they are very slowly travelling toward the south-east, and the quantity of sand is continually increasing. 4°. Memoir on the geology of New South Wales, by C. S. Wilkinson, who recognizes all the great divisions, from the Silurian to the tertiary inclusive, and confirms the truth of the report of the late Rev. W. B. Clarke of the association of triassic plants with the marine carboniferous fauna.

Next follows an account of the three excursions taken by the congress to Florence, Pisa, and Carrara. Accompanying the latter is a section from Carrara to the central region of the Alpi Apuane, in which the Carrara marbles are shown to be of triassic age; fossils of this age being found in, above, and below them.

We next have the prize memoirs on the unification of graphic processes in geological maps. The best was considered to be that by A. Heim; next comes the one by A. Karpinsky, and, lastly, that by M. Maillard. Mr. Heim's memoir contains a plate exhibiting the application of his system to profile sections, which is very clear and plain.

The last or fourth part contains numerous reports on geological nomenclature and coloring of more or less importance. It does not seem to have occurred to the congress to compare the different methods in actual use by the different geological surveys. None of the different reports seems to give these, except that by Major J. W. Powell of the U. S. geological survey. The difficulty, with our still imperfect knowledge of geology, of establishing any system of universal application, seems very great, and is well illustrated by Professor Hébert when he expressed the ingenious wish that votes should only be taken on those points on which all are agreed.

In conclusion, we may mention the very sensible motion of Mr. Torel, that the congress, while leav

ing to the organization committee of each session the care of detailing its programme, desires that in future a place should be reserved for purely scientific studies, besides the works of unification; and also wishes, that, following the example given at Bologna. an exhibition of collections and maps should accompany each session of the congress. J. B. MARCOU.

DEVELOPMENT OF THE MEMBRANEBONES OF THE SKULL OF THE PIKE.

IN an inaugural dissertation presented to the faculty of the university of Jena, which has been published separately, and also in the Jenaische zeitschrift (xvi. 59-87, 1882),1 with two excellent plates, Johannes Walther discusses this subject very ably, and reaches the following conclusions, which are probably of considerable importance as leading to important general views respecting the development of the membrane-bones of the skulls of Teleostei.

The skull of the pike (Esox lucius) consists of membrane and cartilage bones. The former develop in the following ways: 1. As cementuin-bones, by the coalescence of osseous cementum-plates developed below the bases of the teeth, which are formed in invaginations of the oral mucous membrane; 2. As membrane-bones in the subcutaneous connective tissue, independently of any antecedent development of teeth; 3. As perichondrial bones, like the last, but in a deeper layer in contact with the perichondrium. These three modes of development of the parts of the osseous skull are connected together by transitional modes. According to a fundamental biological law, as well as in view of the evidence afforded by the studies of O. Hertwig in the comparative embryology and anatomy of the scales, dermal scutes, etc., of fishes, the preceding types of osteogenesis constitute a series of stages which correspond to the phylogenetic mode of evolution of the bones in question.

The cartilage-bones of the pike's skull develop outwards from the perichondrium, though there is a centripetal growth of osseous tissue during which the cartilage is absorbed. The origin of bone-corpuscles inside of cartilage, or enchondrally, was not observed in any of the stages investigated. The vomer, palatine, and dentary bones are conspicuous instances of the first-mentioned mode of ectosteal development from the fusion of basal, osseous, toothsupporting plates, which the author regards as representing the cementum. The maxillary, jugal, frontal, nasal, parietal, and parasphenoid bones, although not ontogenetically developed in this way, are true membrane-bones, and are derivable primarily or phylogenetically from coalesced basal dentary plates.

The author finds an enamel cap surmounting the conical hollow dentinal bodies of the teeth which contain the pulp. The conical dentinal cap is the first part of the tooth to be formed; the enamelled tip is then developed previous to the anchylosis of the whole to the osseous basal plate, the dentine growing downwards to meet the latter.

The paper also contains observations on the development of the teeth of the young trout, California salmon, common salmon of Germany, and the eel. The morphology of the skull of Esox is very fully and admirably treated, the histological details and crania of the larval stages figured and described constituting a real addition to our knowledge. J. A. RYDER.

1 See also SCIENCE, ¶ 738.

LETTERS TO THE EDITOR.

Rainbow.

LAST evening I observed what to me was a new phenomenon. The day had been clear. Towards sunset the sky clouded in the west with rain-clouds, so that the sun appeared through them only as a white spot of light. The clouds were continuous, but uniformly lighter from the horizon upwards. At quarter of seven o'clock a rainbow, faint, but still distinct in form and color, was visible above and to the northern side of the sun. It extended, perhaps, something less than two-thirds of the way from the horizon in the north to that in the south. The phenomenon is of course easily understood, but is it common? Andover, N.H., May 15, 1883.

Nemestrinidae.

W. J. L.

In the notice of Handlirsch's discoveries as to the life-history of Hirmoneura obscura (SCIENCE, p. 332), I stated (following Osten Sacken's catalogue) that Hirmoneura was the only genus of Nemestrinidae in the United States. Dr. Williston kindly reminds me that I overlooked his description of Rhynchocephalus Sackeni from Washington Territory, published in 1880 (Trans. Conn. acad., iv. 243). He now publishes (Canadian ent., April, 1883) a paper on the North-American species of that family, in which he describes from my collection a third spe cies; viz., Rhynchocephalus volaticus from Florida. While speaking of this dipterous family, I would also mention that Baron Osten Sacken (Wiener ent. zeit., ii. 114) calls attention to a short communication by E. L. Arribalzaga, published in El naturalista Argentino, i. 275 (1878), on the life-history of Hirmoneura exotica Wied., which oviposits in the galleries of a carpenter-bee (Xylocopa augustii St. Farg.). This last constructs its cells in fence-posts and in the wood-work of buildings. Nothing further is stated by Arribalzaga; but the young larvae doubtless leave the burrows, and otherwise resemble those of H. obscura. C. V. RILEY.

Intelligence of the crow.

In SCIENCE, Nos. 13 and 16, are letters bearing this title, in the former of which the writer refers to crows assaulting him while walking in Rome by attempting to drop stones upon him as they circled above. The author of the second letter takes exceptions to the statement, especially to that part of it averring that the crows dropped the stones from their claws, and thinks the narrator must have been mistaken in the bird,' basing his belief on his own experience with crows and ravens in confinement, which he has observed always to use their bills in transporting objects. Whatever the crows may do in Rome,' it is well attested that rooks (Corvus frugilegus), which are true crows, have been seen to carry mussels from the beach to a considerable distance into the air, and let them fall among stones to break the shells, so as to get at the contents. Gulls are well known to occasionally resort to the same practice. Although in neither case do the accounts I have seen state explicitly how the mussels are carried, the inference is that they are taken in the bill. Yet as woodcocks have been seen to transport their young by flying with them supported between the feet, it is obviously unsafe to dogmatize as to what a given species of bird may or may not be able to do. J. A. ALLEN.