THE PELVIS OF THE TESTUDINATA, WITH 



NOTES ON THE EVOLUTION OF THE 



PELVIS IN GENERAL. 



G. BAUR. 



That Sphenodon is the most generalized living reptile there 

 cannot be any doubt to-day. Let us take the pelvis of Spheno- 

 don as a type of reptilian pelvis, and see in what relations the 

 pelvis of the Testudinata and other vertebrates stands. The 

 pelvis of Sphenodon consists of three ossified elements on each 

 side, the ilium, pubis, and ischium, which all meet in the acetab- 

 ulum. The ilium is a simple bone ; pubis and ischium are more 

 complicated, each one consisting of two branches. These con- 

 ditions are best seen in the figure. The inner branch of the 

 pubis may be called entopiibis ; the outer branch, ectopubis (pec- 

 tineal process aut.) ; the inner branch of the ischium, ento- 

 ischiimi ; the outer, ectoischium (metischial process or tuberosity 

 of the ischium, Huxley i). 



E 



Fig. I. — Sphenodon punctatum. Gray. 



E, Epigastroid. 



AI, Mesogastroid. 



H, Hypogastroid. 



P, Pubis. 



/, Ischium. 



/, Foramen pubo-ischiadicum. 



0, Foramen obturatorium. 



The entopubes do not touch each other, nor do the ento- 

 ischia; the entopubes are also separated from the entoischia. 

 This separation is produced by a continuous rod of cartilage 

 placed in the middle line. This cartilage may be called the 

 gastral cartilage, gastrale, ox gastroid. The part in front of the 

 entopubis I call epigastroid (epipubis, part) ; the middle portion, 



1 Huxley, Professor : On the Characters of the Pelvis in the Mammalia, and the 

 Concltisions respecting the Origin of Mammals which may be based on them. Proc. 



Roy. Soc, No. 194, 1879, p. 405- 



345 



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