NATURAL SCIENCES OF PHILADELPHIA. 407 



The superficial laj'er of the other bones is smooth or striate and 

 rugose near articular extremities. The distal end of the head is 

 oblique, and the side below it concave for a short distance. The 

 very short shaft of the phalange is concave, almost emarginate on 

 one margin. The borders of the tubercular head of the rib are 

 thin and broadly flared outwards at the sides. 



M. 



Transverse proximal diameter femur 024 



Anteroposterior diameter Lead of femur 018 



Transverse diameter shaft of femur 015 



Vertical diameter shaft of rib 008 



" " rib at tubercle 016 



" " rib at Lead 006 



Transverse diameter tubercle of rib 008 



Proximal widtli of pLalange 014 



deptli of 007 



LengtL of same pLalange 010 



The remains indicate an animal more robust than airy existing 

 lizard, but probably not so long as some of the larger Varani. 



Clepsydrops collettii, Cope. 



Generic characters. This genus reposes on a series of vertebrae, 

 which includes cervicals, dorsals, and caudals. Associated with 

 these are proximal ends of ribs, a coracoid bone, and some pha- 

 langes, which are provisionally referred to the same. They bear the 

 same relation of size to the vertebrae that the corresponding bones 

 do to the vertebrae of the Gricotus heteroclitus, and have an appro- 

 priately more slender form, like the vertebras in Clepsydrops. 

 They belong in airy case to an allied form. 



The vertebrae on which the genus reposes are more elongate 

 than the corresponding ones of Gricotus. They are deeply bicon- 

 cave, the articular cavities being funnel-shaped and continuous, 

 thus perforating the entire length of the centrum. In a dorsal 

 vertebra the cavities communicate by a very small orifice, while 

 in the posterior, the median contraction of the canal is less marked. 

 The posterior cavity is more gradually contracted than the ante- 

 rior; in the latter the excavation is, in most of the vertebra?, but 

 slight (except beneath the floor of the neural arch), until it falls 

 rather abruptly into the axial perforation. In an ? anterior dorsal 

 it is as wideby excavated at the border as the posterior funnel. 

 Another peculiarity is the absence of processes of the centrum ; 



