No. 3.] PELVIS OF THE TESTUDINATA. 



355 



to the entoischia, leaving a piibo-ischiatic foramen on each side. 

 We have to take a form of pubis as seen in Eryops ^ or Propap- 

 piis,2 as related to the mammalian pelvis, I think it probable 

 that a form of pelvis as seen in Eryops, but not so much ossified, 

 was very near the original form of pelvis seen in Mammals. The 

 pelvis of Sphenodon seems to be in the same relation to that 

 of Pal^eohatteria as the pelvis of Mammals to that of an Eryops- 

 like form, in which ossification was not so much advanced. 



We come now to the Crocodilia and Pterosauria. The pelvis 

 of these groups has always been a puzzle to the morphologist. 

 As it is well known, we find here two elements in front, which 

 do not take part in the formation of the acetabulum. There are 

 two opinions : most of the authors declare these elements as 

 the true pubes ; others say the pubes are united with the ischia, 

 and the elements in question correspond to the marsupial bones 

 in Mammals, or the ypsiloid cartilages in Batrachia. Huxley is 

 of the opinion that the bones are homologues of the marsupial 

 bones in Pterodactyls, but that they represent true pubes in the 

 Crocodiles. 



Before discussing this question, it is necessary to consider 

 the peculiar elements called marsupial bones, ypsiloid cartilages, 

 epipubes. The question is, are these elements portions of the 

 epigastroid cartilage, or are they developed independently from 

 it ? The oldest Batrachia, the Proteida, do not have these ele- 

 ments ; they are well developed in Menopoma, Megalobatrachus 

 and many of the Urodela. According to Wiedersheim, who has 

 made very extensive ontogenetic researches on the pelvis of 

 vertebrates, this portion develops very late : " Ganz zuletzt 

 entsteht die Cartilago epipubis, und zwar in directem Zusammen- 

 hang mit dem allmahlich auftretenden Symphysengewebe. 

 . Dieselbe stellt ein oralwarts gerichtetes, zapfenartiges und 

 anfaenglich noch ganzlich ungegabeltes Gebilde dar." — Afiat. 

 Anz., 1889, Nr. 14, p. 435. 



In a former communication, Wiedersheim was in doubt 

 about the homology of this element : ^ " Uber die morphol- 



1 Cope, E. D., Amer. Nat, 1884, PI. III. 



2 Lydekker, R., Catal. of Foss. Rept. and Amph., Part IV, London, 1890, p. 120, 

 Fig. 26. 



3 Wiedersheim, R. : Zur Urgeschichte des Beckens. Ber.Naturf. Gesellsch., Freibiurg 

 i. B, Vol. IV. 



