1879.] Characters of the Pelvis in the Mammalia, fyc. 401 



nous interspace, as in crocodiles, which represents the cotyloid end of 

 the pnbis (Plate 8, fig. 1). This cartilaginous part of the pubis gives 

 rise to a pectineal process (p.p.), which has. the same position as in 

 birds and in Ornitlwrhynchus. In the floor of the acetabulum, the pubic 

 ossification (fig. 1, Pb.) makes its appearance as a very thin lamina, 

 which extends, underneath the pectineal process, inwards ; and gradu- 

 ally surrounds the whole of the thickened transverse ridge of cartilage 

 which corresponds with the pubis. The pubis is thus represented by 

 an axis of cartilage surrounded by bone, and the thick inner extremities 

 of the two pubes are largely united by fibrous tissue (fig. 10, Sy. p.). 

 The ischia are relatively large, and are united, partly by cartilage and 

 partly by ligament, in a long symphysis (fig. 10, Sy. I.). Their 

 posterior and external angles are produced into short metischial pro- 

 cesses. In one specimen, I observed a distinct sutural line (Plate 8, 

 fig. 11, s), between the anterior curved edge of the right ischium and 

 the corresponding pubis, while no such suture could be traced upon 

 the other side. 



The pelvic arch of Salamandra, therefore, contains all the elements 

 which are found in the higher Vertebrata, but the obturator fon- 

 tanelle is wanting. 



Proceeding from the symphysis pubis, with which it is connected by 

 ligament, is the "ypsiloid" cartilage or epipubis (figs. 1, 11, Ep. p.), 

 which was called by the accurate and acute Duges the "marsupial 

 cartilage." This indication of the homology of the part has been 

 adopted by Cuvier and others, but I do not know that it has been 

 generally accepted. I believe, however, that the identification is 

 perfectly just. 



The ypsiloid cartilage proceeds forwards in the middle line, as a 

 stem (Ep.p.) of variable length, and then divides into two branches 

 (Ep. p., 1 Ep. p. 2 ), which diverge at right angles to one another, and 

 terminate by rounded extremities. The pedicle of the ypsiloid cartilage 

 is broad and triangular in section, the apex of the triangle being dorsal. 



The manner in which the abdominal muscles are connected with this 

 cartilage is very instructive (Plate 8, figs. 13, 15). The anterior pecti- 

 nations of the external oblique muscle (0. e.) are inserted into a' thin but 

 dense fascia, which is hardly separable from the superjacent dermis, and 

 which extends across the middle line to the muscle of the other side. 

 The most posterior bundles of the external oblique, however, are inserted 

 by a rounded tendon into the pectineal process (Plate 8, fig. lb, p.p.), 

 which therefore answers to the spine or tuberosity of the pubis in 

 Mammalia. Internal to this, the fascia arches over a small space (i.r.) 

 (which corresponds with the inguinal ring), and is then inserted into 

 the whole length of the pedicle and into the posterior half of each ramus 

 of the ypsiloid cartilage. Beyond this point the rami are free externally, 

 though they lie close against the fascia. On their inner sides, however, 



