60-B THE EXTINCT BATRACHIA, REPTILIA 



M. M. 



Length, .075 Inner, .005 



Proximal expanse, outer measurement, .052 

 The portion of the pelvis preserved consists of the proximal halves of left ilium and ischium, the anterior portion 

 of the latter being broken away. This fragment is not Dinosaurian; the longitudinal expansion forbids the reference 

 of the ilium as the ischiopubis of a Dicynodont, and the ischium is too different to be regarded as the scapula of a 

 Belodont. It presents a broad shallow concavity as acetabulum, which on the inner face is grooved and ridged at the 

 inferior margin, as though united to the ischium by suture. This is well shown in Emmons' figures of the same bone 

 of another species, in North Amer. Geology, PL VI. The upper plane of this element is abruptly curved backwards 

 and then broken away. The supposed ischium presents a marked acetabular articular face at its posterior connection 

 with the ilium. Its posterior margin is much thickened, and becomes decurved towards the symphysis, which is lost. 

 It sends a limb anteriorly along the line of union with the ilium, and apparently terminates in a narrow obtuse ex- 

 tremity with rugose margins. Its supposed obtruator margin is thickened along this process; the main body of the 

 bone is flattened at a strong angle with the posterior margin, and turned away anteriorly like the ilium of a Dicyno- 

 dont, and includes an incomplete oval foramen with the acetabular process. The two pelvic elements are crushed 



nearly into one plane. 



M. 31. 



Length of fragment, 0.167 Width ischium at foramen, .055 



" ilium to posterior process, .0715 Thickness " distally, .021 



" iliac suture of ischium, .092 



The mode of attachment of the pubis is not indicated in this specimen, but it was evidently quite different from 

 that in the Crocodilia. 



The femur is that of the left side; it is perfect, except that the portion usually supporting the third trochanter is 

 broken out; say two inches. The head is Crocodilian, i. e., without neck and compressed in one plane. Its extrem- 

 ity is slightly convex inwards, the inner extremity thickened, convex and decurved; the extero-posterior thinned and 

 curved backwards slightly. The margin continued from the latter is therefore thinned, though obtuse edged, and 

 encloses a wide shallow groove with the inner, thickened margin. There are no distinct trochanters. The shaft is 

 quite slender, obliquely spherical triangular in section, with an inner ridge in front, and outer behind. The medul- 

 lary cavity is very small. At the distal third the shaft is flattened antero-posteriorly. The trochlear groove is wide 

 and shallow, and the condyles project less posteriorly than is usual; they have, however, been under considerable 

 pressure. The inner is wider and shallower, the outer narrower and deeper. Their extremital faces are separated by 

 an open notch. 



The fibula is a long slender bone, having a slight sigmoid flexure, and ridges twisted round the flattened shaft. 

 The extremities are more flattened, both in the same plane; the proximal is broken away; the distal is obtuse, one end 

 terminating in a point; the surface rugose. Its form is Lacertilian. 



M. M. 



Length femur, restored, 0.34 Diameter condyles, inner, fore and aft, 0.045 



Diameter head, anteroposterior, 0.09 Length fibula, broken, 0.24 



" " transverse (greatest), 0.044 Diameter perfect extremity, 0.035 



shaft at middle, 0.045 " imperfect " 0.042 



" condyles, transverse, 0.083 " shaft, 0.025 



What is doubtfully referred as a distal phalange, resembles that ascribed to a species of the genus by Meyer, but 

 as I cannot find lateral grooves, and the proximal articulations are concealed by matrix, it may not be such. One 

 lateral margin is obtuse, the other acute; body thinned out to tip, flat in cross section below, concave in longitudinal, 



as wide distally as proximally. 



M. M. 



Length, .035 Depth proximally, .0165 



Width distally, .017 



Surface striate-rugose; lines of the upper surface converging toward a median point from the base. 

 Several more or less broken, and one complete rib are preserved. The two heads are distinct. The perfect rib 



