spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by de Beer, G. R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by de Beer, G. R.

Quarterly Journal of Microscopical Science, Vol s2-75, 307-320, Copyright © 1932 by Company of Biologists

Memoirs: On the skeleton of the hyoid arch in Rays and Skates

G. R. de Beer

1. The relations to the afferent pseudobranchial artery of the lower ray-bearing part of the hyoid arch skeleton in Rays show that the latter is not the ceratohyal, but a pseudohyoid.

2. Investigation of the development of Torpedo shows that the pseudohyoid arises distinct from the hyoid bar, and that the ceratohyal is much reduced.

3. The ceratohyal in Rhynchobatus is not so much reduced as in Torpedo, Pristis, or Raja, and it still bears a small number of hyal rays.

4. The pseudohyoid is formed as the result of fusion of hyal rays, and pseudohyoid bars are present more or less well developed in a large number of Sharks.

5. The enlargement of the pseudohyoid and reduction of the ceratohyal in Rays is associated with the increased distance between the mouth and the first gill-slit, and the necessity for providing a support for the hyal rays and the anterior wall of the first gill-slit. Similar factors have been operative in the Dipnoi and have led to analogous results.






© The Company of Biologists Ltd 1932