Page images
PDF
EPUB
[ocr errors][merged small]

On the Areas of the Axis Cylinder and Medullary Sheath as

seen in Cross Sections of the Spinal Nerves of Verte-
brates. By Henry H. DONALDSON and G. W. Hoke.
(From the Neurological Laboratory of the University of

Chicago.) With one figure.
On the Number and Relations of the Ganglion Cells and Medul-

lated Nerve Fibers in the Spinal Nerves of Frogs of Dif-
ferent Ages. By Irving HARDESTY. (From the Hearst

Anatomical Laboratory of the University of California.)
Editorial

17

Psychology and Neurology.

The International Commission on Brain Research. Literary Notices.

57 62

65

THE JOURNAL OF COMPARATIVE NEUROLOGY AND PSY. CHOLOGY is published bi-monthly. The annual volume of six numbers comprises about 500 pages, with plates and text-figures. The subscription price is $4.00 a year, strictly net (foreign subscription, $4.30, 18 s., M. 18, 22 fr., L. 22), postage prepaid.

Authors receive 50 reprints of their papers gratis and additional copies are supplied at cost. All MSS. and matter for review relating to the Structure of the Nervous System and all business correspondence should be addressed to the MANAGING EDITOR AT Denison UNIVERSITY, GRANVILLE, Ohio. Editorial Matter relating to Comparative Psychology and the Physiology of the Nervous System should be sent directly to DR. ROBERT M. YERKES, PsychoLOGICAL LABORATORY, HARVARD UNIVERSITY, CAMBRIDGE, Mass.

Entered a second-class matter in the Postoffice at Granville, 0.

[blocks in formation]

ASSOCIATED WITH
OLIVER S. STRONG,

HERBERT S. JENNINGS,
Columbia University

University of Pennsylvania

COLLABORATORS

J. MARK BALDWIN, Johns Hopkins Uuiversity
FRANK W. BANCROFT, University of California
LEWELLY& F. BARKER, University of Chicago
H. AEATH BAWDEN, Vassar College
ALBRECHT BETHE, University of Strassburg
GE COGHILL, Pacific University
FRANK J. COLE, Odiversity of Liverpool
8. L. CRAMPTON, Columbia University
C. B. DAVENPORT, Upiversity of Chicago
WM. BARPER DAVIS, Lehigh University,
HENRY H. DONALDSON, University of Chicago
LUDWIG EDINGER, Frankfurt a-M.
8,1.

FRANZ, McLean Hospital, Waverley, Mass. THOMAS H. HAINES, Ohio

State Univorsity
A. VAN GEHUCHTEN, University of Louvain
RG. HARRISON, Johns Hopkins University
C.F. HODGE, Clark University
8. J. HOLMES, University of Michigan
EDWIN B. HOLT, Harvard University
G CARL HUBER,'University of Micbigan
JOSEPH JASTROW, University of Wisconsin
J. B. JOHNSTON, West Virginia University

B. F. KINGSBURY, Cornell University
FREDERIC 8. LEE, Columbia University
JACQUES LOEB, University of California
E. P. LYON, St. Louis University,
ADOLF MEYER, N. Y. State Pathological Inst.
THO8. H. MONTGOMERY, Jr., Univ. of Toxas
WESLEY MILLS, McGill University
C. LLOYD MORGAN, University College, Bristol
T. H. MORGAN, Columbia University
A. D, MORRILL Hamilton College
HUGO MUENSTERBERG, Harvard University
W. A. NAGEL, University of Berlin
G. H. PARKER, Harvard University
STEWART PATON, Jobps Hopkins University
RAYMOND PEARL, University of Michigan
C. W. PRENTISS, Western Reserve University
C. 8. GHERRINGTON, University of Liverpool
G. ELLIOT SMITH, Gov't. Medical School, Cairo
EDWARD L. THORNDIKE, Columbia University
JOHN B. WATSON, University of Chicago
W. M. WHEELER, Am. Museum of Nat. History
C. 0. WHITMAN, University of Chicago

Published bi-monthly
DENISON UNIVERSITY, GRANVILLE, OHIO

[graphic]
[blocks in formation]

By IRVING HARDESTY.
(From the Hearst Anatomical Laboratory of the University of California.)

With four figures in the text.

Some months ago a zoo in San Francisco lost by sudden death two specimens of Emu (Dromaeus novae-hollandiae) and the management very kindly delivered the carcasses to me within a few hours after death. The birds were immediately dissected and, with certain of the other organs, the central nervous system of each was removed and preserved in 10% formalin.

The specimens were full grown and considered of large size, being nearly as large as the adult ostrich. With the exception of the head and upper part of the neck, the bird resembles the Cassowaries; but it is larger, its neck relatively longer and it belongs to a different genus. In general size of the body it is intermediate between the Rhea, or South American ostrich, and the ordinary or African ostrich (Struthio camelus). The head, though less bare, is very similar to that of the ostrich, while most of the neck, unlike the ostrich, is covered with the long streaming plumage common to the rest of the body. The wings are even more rudimentary than those of the ostrich, being nothing more than slender stubs entirely hidden in the plumage and even void of spiny rudiments of wing feathers. Similar to the ostrich, the legs are bare but somewhat shorter in proportion than those of the ostrich and are relatively more stout, the drumstick” being nearly as large in circumference as the thigh of a medium sized man.

The spinal cord of such an animal necessarily presents features of unique interest and preparations were made with the intention of describing it. Meanwhile, however, the paper of STREETER ('04) appeared giving a description of the spinal cord of the ostrich and on comparison it was found that the spinal cord of the emu, in its general features, is apparently so similar to that of the ostrich that a full description of it was deemed unnecessary. STREETER's desrcription of the one may be referred to for the most part as a description of the other.

This paper, therefore, may be limited to a few of the fea. tures presented in the spinal cord of the emu not touched upon by STREETER for the ostrich and to some further observations upon one or two points less fully treated by him.

In the lumbar enlargement alone STREETER mencions having observed a segmented appearance (“'neuromeres”) in the ostrich cord. He does not refer to such as present in other localities and little more than mentions it in the lumbar region. After noting a few of the general macroscropic features of the emu cord, some attention will be given here to the appearance of evident segmental enlargements in other localities, as well as in the lumbar region. In this respect it may differ from the spinal cord of the ostrich.

Lying in the vertebral canal, the spinal cord of the emu is surrounded by an epidural cavity which is somewhat larger in proportion than is usual in the more commonly studied mammals. The dura mater has an unusually smooth outer surface. Between the nerve pairs of the adjacent segments it appears thicker along the ventral and ventro-lateral aspects of the cord than along the dorsal aspect, while at the levels at which the nerves are attached it appears thicker along the lateral surfaces. From a number of measurements, made later from stained sections, the thickness of the dura mater was found to vary from 87 kl to 146 y, withan average thickness of 113 4. The arachnoidea is similar in proportional thicknesss and arrangement to that usually found in the mammals. The pia, however, is relatively thick as compared with that of the mammalian cord. It is well defined as to its outer surface and so thick as to be easily stripped from

« PreviousContinue »