Coe and Kunkel— California Limbless Lizard. 371 
Ribs.—The ribs are slender, graduaily tapering and curved (pl. 
xLu, fig. 13). They increase in length to the tenth and then grad- 
ually diminish, The anterior ribs incline more posteriorly than the 
rest. The articular facet is triangular with the apex of the triangle 
directed ventrally. There isa single rounded notch at the middle 
of the base of the triangular facet, which is slightly concave. 
Posteriorly they become circular, The last two ribs are consider- 
ably shorter and slightly stouter than the rest. 
Pelvis.—The shoulder girdle is entirely wanting. The pelvic 
girdle is very rudimentary and is represented solely by a pair 
of somewhat flattened, rod-like bones (pl. x1, fig. 14) attached 
by ligaments to the extremities of the transverse processes of the 
second sacral vertebra and extending medially and anteriorly in 
front of the cloacal aperture. The anterior ends of the pelvic 
rods are not constant in the degree to which they approach each 
other, but they never come in contact. Each presents a slight trian- 
gular process on its ventral and inner side about one third the dis- 
tance from the anterior to the posterior end. Baur states that he 
found in a macerated skeleton that the girdle was differentiated into 
an ilium, ischium, and pubis, but in a careful study of the adult and 
in sections of late embryos I have been able to find but a single bone 
and have seen no indication whatever of more than one center of 
ossification. Baur also found an obturator foramen, which does not 
appear in my preparations. Serial sections of the embryos and 
adults showed a simple cylindrical rod of cartilage with rounded 
ends situated in the middle line ventral to the bladder and anterior 
to the pelvic bones. It probably represents the epipubis. 
II].—UrocGenirat ORGANS. 
W. R. Cor anp B. W. KunkeEt. 
Pl. xu, figs. 25, 26; Pl. xuiv, figs. 27-32; Pl. xxv, figs. 33-37; Pl. xivt, 
figs. 38-45 ; Text-figs. 14, 15. 
The material on which these studies were made was collected at 
Pacific Grove, California, during the months of August and Septem- 
ber, 1901. At this time of the year the female lizards give birth to 
their young. Some of the females collected had already discharged 
their young while others still carried embryos, all of which were in 
an advanced stage of development. Some of the embryos, however, 
