Maryland Geological Survey 367 



Description. — Man us rhombic, the length of the palm not much exceed- 

 ing the width, somewhat more convex on the outer than on the inner face, 

 the outer surface neither abruptly nor deeply deflexed near the posterior 

 margin. Surface smoothish, with some tubercles on each side of the slight 

 excavations on both sides of the hand near the commissure between the 

 bases of the fingers; the acute lateral edges of the hand crenulated, as in 

 C. mortoni, but the lower edge is not deflexed posteriorly as in that species. 

 Pollex triangular in section, the angles crenulated, the flat grasping face 

 with a short smooth rib near the base, which joins the keel along the outer 

 angle of the pollex. There is no tooth on the pollex. 



Length of manus about 30 mm. ; exclusive of pollex 18.5 ; width 16.5 ; 

 thickness 7.6 mm. 



In a few specimens of the paratypic lots the dactylus remains as a short 

 stump only. No carpus or other part is known from the New Jersey 

 localities. Thirteen hands, probably belonging to as many individuals, 

 are before me, the most perfect being one of two in the collection of the 

 Wagner Free Institute of Science. 



The manus of C. conradi differs from that of C. mortoni in being much 

 shorter and broader; more evenly convex on the two sides, the posterior 

 margin of the outer side and the keel along the upper edge are not abruptly 

 deflexed behind ; the pollex of C. conradi has no median tooth on its grasp- 

 ing face, which is flat with a short smooth ridge and bounded by two crenu- 

 late angles, while in C. mortoni there is a median tooth, a crenulate ridge 

 on the face, and no crenate angle along the lower inner part of the pollex. 



The carpus in a specimen from Brooks estate near Seat Pleasant (pi. A, 

 fig. 4) is more compressed than that of C. mortoni, with the proximal end 

 more oblique, and the short, tuberculate carina near the distal angle is 

 much less developed. There is a row of punctures along the distal border. 



Two specimens from two localities in Maryland seem referable to this 

 species. That from the Brooks estate consists of a hand, not quite perfect, 

 and the natural mold, which shows also part of the impression of the 

 dactylus, part of the carpus and part of the merus. The specimen from 

 Seat Pleasant is small, a hand with broken fingers. It appears that the 



