tives of high power and short working distance, may become, with low powers, large enough to destroy the usefulness of the common methods of measurement of the lenses measured, a 34inch varied from 36° to 38° telescopic aperture to 392° microscopic, while a 3-inch ranged from 131⁄2° to 19°. Change of draw-tube caused a variation of several degrees.

A NEW JOURNAL.-The (English) Postal Microscopical Society has undertaken the publication of a quarterly jourhal, the first number of which appeared in March. It is edited by the very able Hon. Sec'y of the Society, Mr. A. Allen, of Bath, and published by W. P. Collins, of London. Its primary object is the preservation of the most important notes and drawings from the note-books of the Society; but it will also contain original papers, notes, extracts, and correspondence upon microscopical subjects. It will be freely illustrated, and will doubtless prove an entertaining and instructive visitor.

SUMMER SCHOOL OF BIOLOGY.-Microscopists can enjoy rare opportunities for sea-shore collecting and laboratory work, at the Summer School of Biology of the Peabody Academy of Science, which opens at Salem, Mass., on July 11, and continues four weeks. Among the special advantages for microscopical students, will be a course of lectures on physiological botany, by Professor C. E Bessey, of Iowa, and a course on anatomy and physiology of vertebrates, by Professor A. H. Tuttle, of Ohio.

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SCIENTIFIC NEWS.

- It appears that the hunting of alligators in Florida is carried on to such an extent as to threaten the extirpation of the species there. Nothing is used except the skins on the belly and legs. The rough scaly plates on the back are rejected. The heads are cut off and buried for a few days, till the tusks can be detached. It was announced lately that one person had collected alligators' teeth to the amount of three hundred and fifty pounds. This will give some idea of the destruction going on. On the St. John's river a new method of hunting has been devised. A dark lantern, with a powerful reflector, is used on suitable nights; and no difficulty is experienced in approaching the quarry. The animals seem bewildered with the strong glare, and make no effort to escape. The gun is held within a few feet of the head-a touch to the trigger, and there is one "gator" less in Florida. This process is very effective, and the hunters are enabled, not only to kill, but to secure their prey. Large numbers of these animals are slain annually by tourists for amusement only, besides those slaughtered for profit. Further, many young alligators are stuffed as specimens, or sent off alive as curiosities, while myriads of eggs are blown or disposed of by dealers.-English Mechanic.

-The views of Dr. Hahn, as to the presence of organic structures in meteorites, have been refuted by Professor Carl Vogt, who, in a memoir presented to the French Academy of Sciences, affirms that Dr. Hahn has no foundation for his conclusions, and that in no single case do the pretended organic structures present the microscopic appearance of the organisms for which they have been mistaken.-English Mechanic.

- G. T. Wetterman, Director of the Museum Koninklijk Zoölogisch Genootschap, Amsterdam, Holland, writes that within a short time the new aquarium buildings, recently erected in the gardens, will be opened, not only for the recreation of the members. of the society but to audiences for the academical course of zoölogy, as well as for laboratories for anatomical research. Director Wetterman states that naturally all sorts of sea animals will be needed for the work, and requests the addresses of aquaria in America that will enter into a mutual exchange of marine animals or will dispose of them by sale. He expresses a wish to have as much as possible of the American submarine fauna represented in their tanks.

-James Geikie, LL. D., author of the "Great Ice Age," and for twenty-one years a member of the Geological Survey of Great Britain and Ireland, has recently received the appointment to the Murchison Professorship of Mineralogy and Geology in the University of Edinburgh, made vacant by the appointment of his brother, Professor Archibald Geikie, to the director-generalship of the Geological Survey. He has resigned his position in the survey and enters upon his duties in the University in May.

But two summer schools of science will apparently be opened to students this coming season, one at Annisquam, Cape Ann, Mass., under the charge of Professor A. Hyatt, curator of the Boston Society of Natural History; the other is the summer school of biology of the Peabody Academy of Science, Salem, Mass. Both offer good facilities for study.

We are asked by Professor E. S. Morse to correct a mistake on page 326 of the NATURALIST in reference to the Japanese students. Mr. Ijima and Mr. Iwakawa have never been abroad, what they have acquired has been learned in Japan. Mr. Mitsukwri was a fellow at Johns Hopkins University and was a student of Professor W. K. Brooks.

The Princeton College Exploring Expedition obtained a skull of the Eocene mammal Achanodon insolens Cope, whose position has been heretofore doubtful. It turns out to be a flesheater of the family Arctocyonida, and is the largest species known. It was a formidable animal, as large as a brown bear, and is probably the ancestral type from which bears were derived. Messrs. Scott and Osborne will publish a memoir on it in the Contributions of the Museum of Geology and Archæology.-E. D. Cope.

PROCEEDINGS OF SCIENTIFIC SOCIETIES.

NATIONAL ACADEMY OF SCIENCES.-The Academy met in the National Museum, Washington, on Tuesday, April 18, 1882, President W. B. Rogers in the chair. The papers of the first day were:

1. The course of the Gulf stream since the Cretaceous period, Alexander Agassiz. 2. The Pre-cambrian rocks of Italy, T. Sterry Hunt. 3. Notes on the geology of Yucatan, Alexander Agassiz. 4. Desiccation of the Plateau of Mexico, Alexander Agassiz. 5. On the brain of Phenacodus, E. D. Cope. 6. On the young stages of a few osseous fishes, Alexander Agassiz. 7. The affinities of Palæocampa Meek and Worthen, as evidence of the wide diversity of type in the earliest known Myriapods, S. H. Scudder. 8. On the genesis and development of the Chiropterygium from the Ichthyopterygium, Theodore Gill.

Wednesday, April 19, 1882.-9. Preliminary notice of a new Dividing Engine, H. A. Rowland. JO. On photographs of the spectrum of the nebula in Orion, Henry Draper. 11. Theory of concave gratings, H. A. Rowland. 12. On the influence of time on the change in the resistance of the carbon disk of Edison's Tasimeter, T. C. Mendenhall, presented by G. F. Barker. 13. Note on a special form of secondary battery or electric accumulator, Wolcott Gibbs. 14. Researches on complex inorganic acids (continued). Wolcott Gibbs. 15. Biographical notice of Professor John W. Draper, G. F. Barker. 16. Some discoveries that enhance the value of the cotton and orange crops, C. V. Riley.

Thursday, April 20, 1882.-17. The relation of rain-areas to areas of low pressure, Elias Loomis. 18. Description of an Articulate of doubtful relationship from the Tertiary beds of Florissant, Colorado, S. H. Scudder. 19. Mythology of the Zuñi Indians, F. H. Cushing. 20. On the polarization of the light of the Moon, A. W. Wright. 21. On the results of the incandescent lamp tests at the Paris Exhibition, G. F. Barker. 22. On the infra-red portion of the solar spectrum as studied with the bolometer, S. P. Langley.

Friday, April 21, 1882.-23. On the formation of metalliferous vein formation at Sulphur Bank, California, Joseph Leconte. 24. On a form of standard Barometer, A. W. Wright. 25. On a marsupial genus from the Eocene, E. D. Cope. 26. On a fallacy in induction, C. S. Peirce. The committee to examine into the investigations into the value of sorghum as a source of sugar, made an interesting report. Professor Ira Remsen, of Baltimore, was elected a member.

PHILADELPHIA ACADEMY NATURAL SCIENCES, Dec. 13-Mr. Ryder described the development of fish eggs. He agreed with His and Rauber in the opinion that the rim of the blastoderm goes to form a part of the muscular plates of the side of the body.

Dec. 20.-Mr. Martindale read a history of the connection of Dr. Ruschenberger with the academy, as testimony to his services, on the occasion of his declining re-nomination to the presidency.

Dec. 27. As the result of the annual election it was announced that Dr. Jos. Leidy was duly elected president of the Academy.

Jan. 3, 1882.-Mr. Ryder confirmed, by the result of his observations on additional types, the formation of vacuoles in the notochord of teleost fishes; and stated that although the tissue of the neural and enteric portions of the neurenteric canal were continuous, no open canal connected those portions. Dr. Leidy called attention to the composition of the gravels of Philadelphia and its vicinity, The commonest pebbles are quartz or quartzite, while those next in frequency are red-sandstone, probably mesozoic. Conglomerates are also found, but fossiliferous pebbles are very

rare.

Jan. 10. Mr. Heilprin called attention to the tidal theory of Professor Ball, and stated that the existence of life upon the coast tended to nullify some of Professor Ball's conclusions.

Mr. Potts described a new sponge, Heteromeyenia ryderi, also a new species of Tubella, which he named T. pennsylvanica. The seed-bodies of this latter sponge range from to 7% of an inch in diameter. He showed how the statoblasts of sponges like Spongilla fragilis and Carterella form layers upon rocks, etc., after the spicules of the sponge have been washed away. The subject of the algous parasitic chlorophyll cells in certain sponges, infusoria, and mollusks was discussed by the president and Mr. Ryder.

Mr. Meehan related an incident which indicated that sparrow*hawks can see mice when perched at a horizontal distance of 500 feet.

Jan. 17.-Papers upon the new Crinoids of the Chemung period from the State of New York, by H. S. Williams, M. D.; the Species of Odontomya found in the United States, by Dr. L. T. Day, and a new station for Corema Conradü, by Aubrey H. Smith, were presented for publication. Mr. Redfield spoke of the extreme rarity of C. Conradii.

MIDDLESEX INSTITUTE. Feb. 28.-L. L. Dame, president, delivered an instructive lecture, the first in a series of twelve weekly botanical lectures, on the "Growth of the plant from the seed," to a class of nearly fifty members.

March 7.-Mrs. A. J. Dolbear gave the second in the series, her subject being, "Morphology of roots, stems, and branches."

March 8.-President Dame briefly reviewed the first year's work of the Institute, and made some excellent suggestions in regard to the best manner of carrying on the work which the Institute had undertaken.

ON SOME ENTOMOSTRACA OF LAKE MICHIGAN AND ADJACENT WATERS.

ONE

BY S. A. FORBES.

NE cannot go far in the study of the system of organic life which prevails in a stream or lake, without being made aware of the important part played therein by the neglected but interesting group of the smaller crustaceans. They occupy a central position not only in the classification of aquatic animals, but also in the complicated network of physiological relations by which the living forms of a body of water are held together as an organized society. Feeding, themselves, upon the lowest and smallest of plants and animals, they furnish food in turn to a great variety of the higher animals, and even to some plants.1

The fisherman who toils at his nets, the sportsman in pursuit of health and recreation, rarely reflect, even if they know, that their amusements and their labors depend strictly upon these humble creatures, of whose very existence, indeed, many of them are unaware; and yet there is ample evidence that, with few and unimportant exceptions, all young fishes, of our fresh waters at least, live for a time almost wholly upon entomostraca.2 If de

'In ten "bladders" of Utricularia vulgaris, taken at random, I found ninetythree animals, either entire or in recognizable fragments, and representing at least twenty-eight species. Seventy-six of the animals found were Entomostraca, and belonged to twenty species. Nearly three-fourths of both individuals and species were Cladocera. Just one-third of all the animals found in these bladders belonged to the single species Acroperus leucocephalus Koch.

On the Food of Young Fishes. By S. A. Forbes. Illinois State Laboratory of Natural History, Bulletin No. 3, November, 1880, pp. 66–79.

On the First Food of the Whitefish. By S. A. Forbes, Normal, Ill. The American Field, Vol. XVII, No. 11, p. 171, March 11, 1882. 36

VOL. XVI.-NO. VII.