Observations on the development of Raia batis.

  • Wyman, Jeffries, 1814-1874.
Date:
[1864?]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the development of Raia batis. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    1/14
    II. Observations on the Development of Eaia By JEFFRIES WTMAN, M. D., BATIS. HERSEY PROFESSOR OP ANAf( ARD COLLEGE. Communicated January 27th, 1864. The following observations relate mostly to the changes which a single specks skate undergoes in its outward form and strnctnre daring development. They are based ^ the examination of a series of eggs, collected in the spring of 185! and of the three subsequent years The publication of them has been delayed in the hope that other specimens might be obtained which would make it practicable to give an account of the evolution of the internal organs. Having been disappointed in tins, it was thought desirable to publish such results as have already been reached beW.ng that some of then,, at_least,are .ddjfepe to the 2,,„vic fc.^wfcdge of the Egg case. - This singular structure has the general form of such parts in «. laying Selachians. The whole case, in the species here described, is between six and seven inches in length, of a deep greenish-brown color, and composed of minute parallel filaments, which give it a striated appearance and a silky lustre The cen tral pouch (fig. 1, «), for the protection of the yelk and the embryo, is about two inches long, an inch and a half wide, bulges in the middle, and has a hollow slender curved horn projecting from each corner. The fore end of the pouch is deeply con' cave, and thickest, while the hinder is thin, nearly square, and ragged- it is from this part that the embryo escapes, after the separation of the upper and under walls from each other. The hinder horns project backwards as they lie in the oviduct and are of about twice the length of those at the other end. The outer edge of