386 5. W. WILLISTON 



The fingers are remarkable, so far as they are preserved. The 

 great size of the ulnar ones over the radials suggested at first the 

 possibiHty of error in their determination. As shown in the illustra- 

 tion, the unbroken lines represent bones of the more complete 

 specimen, while those shown in dotted lines are taken from the 

 other two specimens as they lie in place. There can be no legiti- 

 mate doubt of the phalangeal formula, 2, 3, 4, 5, 3. Not a few 

 slender phalanges are preserved loosely, belonging in the fingers. 

 The claws are elongated and sharply pointed. 



PELVIC GIRDLE AND EXTREMITY 



Pelvis (Fig. 4, V). — The more or less complete pelvis is pre- 

 served in three different specimens. In addition, there are two 

 isolated ischia preserved in small nodules ; one of these is of a young 

 animal, the other of a nearly full-grown one, though a trifle smaller 

 than the largest. These two small ischia have been used to com- 

 plete the drawings made from an adult specimen. The pubes in 

 the three associated skeletons shown in the figures are determinable 

 in all details. The ilia are concealed in the pelves associated with 

 the vertebrae, but there are two incomplete ones that were found 

 free in the clay, in perfect preservation, save for the loss of the 

 greater part of the posterior process. 



The ilium, so far as it is determinable, shows no peculiarities 

 of note to distinguish it from the common pelycosaur type, espe- 

 cially that of the poliosaurids. It has a rather slender posterior 

 process, like that of Varanosaiirus. Nor is the ischium at all 

 peculiar; it is, indeed, of the form of all the ischia known of the 

 American Permian, meeting its mate in a broad symphysis, and 

 doubtless forming a more or less spout-shaped orifice to the pelvis. 

 The pubis, however, departs markedly from the universal pely- 

 cosaur type, that observed in Dimetrodon, Sphenacodon, Varano- 

 saurus, etc., agreeing rather better with that of Casea. In the 

 fully adult specimens it meets the ischium in a nearly complete 

 sutural union, leaving no puboischiadic vacuity, or a very small 

 one, such as is always found in the true pelycosaurs. It is sub- 

 quadrate in shape, with its superior outer margin somewhat 

 thickened and emarginate, but not forming a spout-like anterior 



