REPTILIA : CLEPSYDROPS 73 



as is not unlikely, it is definitely proven that the original types are 

 equally, perhaps more, characteristic of a genus distinct from that 

 including the Texas species referred to Clepsydrops, it would be in 

 defiance of common sense to introduce a new name for the latter 

 because the identity of its type is in dispute. 



Clepsydrops natalis (?) Cope, Proc. Amer. Phil. Soc, XVII, 509, 529, 1878; 

 Case, Pelycosauria, 42, 90, Pis. IV, V, VI, 1908. 



Among the material from the Craddock bone quarry there are 

 numerous limb bones and other parts of the skeleton which agree 

 so closely with the descriptions, and especially with the figures, of 

 this species as given by Case, that I believe there can be little 

 doubt of their correct determination. They are, like all other 

 specimens from this quarry, in such excellent preservation that I 

 have given figures of many of them and rather full descriptions. 

 That they all belong in the same species is doubtful, however. 



Femora. — Two forms of femora are shown in Plate XXX, 

 Figs. 1, 2, and Plate XXXII, Fig. 1. The upper extremity is 

 truncate, the surface subcrescentic in outline, much narrower in 

 the femur shown in Fig. 1 than in that of Fig. 2. The trochanteric 

 ridge is high up; the digital fossa shallow. The distal extremity 

 is slightly convex dorsoventrally; the outer condyle is usually 

 much broader; both the popliteal and extensor grooves are shallow. 

 The stouter femur has decidedly thicker ends and is a little wider 

 than the other. The shaft is oval in cross-section, and is more 

 slender in the one shown in Fig. 1 than that of Fig. 2. These 

 differences seem too great for specific identity. The slender 

 femur may be provisionally designated as Clepsydrops A.; the 

 more robust as B. In addition to the larger femora of nearly 

 uniform length there are numerous ones in the collection, one of 

 which is shown in Plate XXX, Fig. 3, of much smaller size, agree- 

 ing better with Clepsydrops A., save that, as would be expected 

 of juvenile bones, the ends are less well ossified. 



Tibia. — A left tibia, which in size seems to agree well with the 

 larger femora, is shown in Plate XXX, Fig. 10, and may be 

 referred to one or the other of the forms represented by the femora, 

 perhaps better with the more slender one; it is very perfect. 



