1879.] Characters of the Pelvis in the Mammalia, Sfc. 405 



term of a series of smaller-brained Ornithodelphia. Among the higher 

 Vertebrata, I think that there is strong reason to believe that edentu- 

 lous animals are always modifications of toothed forms. 



EXPLANATION OF PLATE 8. 



Figs. 1 to 9. The left half of the pubic arch in Salamandra (fig. 1), Iguana 

 (fig. 2), Crocodilus (fig. 3), Ornithorhynchus (fig. 4), Echidna (fig. 5), 

 Lepus (fig. 6), Compsognathus (fig. 7), Laosaarus (fig. 8), and Apteryx 

 (fig. 9). The letters have the same signification throughout. II. ilium, 

 Pb. pubis, Is. ischium, Up. p. epipubis, S. a. sacral axis, Ip. a. ilio-pectineal 

 axis, Ob. a. obturator axis, II. a. iliac axis, Sy. p., Sy. I, indicate the 

 extent to which the pubes and the ischia unite respectively in their 

 ventral symphyses ; p. p. pectineal process, t. p. tuberosity or spine of the 

 pubis, m. p. metischial process or tuberosity of the ischium, CI. os cloacae 

 in Iguana. 



Figs. 10, 11. Dorsal and ventral views of the ventral half of the pelvis of Salamandra 

 maculosa (x4). The letters as before, except Epp. 1 Epp. 2 , right and left 

 rami of the epipubis or ypsiloid cartilage, Ob. n. foramen of the obturator 

 nerve, s. trace of a suture between the ischium and the pubis on the right 

 side, Ac. acetabulum. 



Fig. 12. "Ventral aspect of the pelvis of a small Crocodilus acutus and the hinder- 

 most abdominal false ribs, of the natural size. The obturator nerve 

 (Ob. n.) perforates the aponeurosis, which fills up the rhomboidal space 

 between the ischia and the pubes, on the inner side of the pubis. Sy. p. I. 

 the ligamentous union of the pubes. 



Fig. 13. Dorsal aspect of the epipubis and the muscles connected with it in 

 Salamandra maculosa. On the left side, the transversalis and the 

 muscle C. are removed. 



Fig. 15. The same, all the muscles but the external oblique being removed. 



Fig. 14. The epipubis and the adjacent muscles in Ornithorhynchus. 



R. rectus abdominus, Py. pyramidalis, 0. e. obliquus externus, Trs. transversus, 

 I. a. linea alba, f. fascia, extending between the two rami of the epipubis 

 in Salamandra, P. I. the representative of Poupart's ligament, i. r. inguinal 

 ring, A. B. C. muscles of Salamandra described in the text. A. and C. 

 together appear to be the pubio-marsupial of Duges : P. is the hebosteo- 

 glossus of von Siebold. 



March 13, 1879. 



THE PRESIDENT in the Chair. 



The Presents received were laid on the table, and thanks ordered for 

 them. 



The following Papers were read : — 



