364 Systematic Paleontology 



Description. — Manus rhombic, its breadth about two-thirds the length, 

 the surface nearly smooth. The outer face is very convex, the greatest 

 convexity being posterior and near the upper or dactylus side; there is a 

 series of four punctures extending backwards from the base of the pollex, 

 and three punctures on the same convex side; the posterior margin 

 abruptly falls near the joint, a prominence bearing a group of small 

 tubercles at the summit before the deflection. Inner surface or palm 

 (fig. 1) much less convex than the outer, becoming concave near the 

 lateral margins, nearly smooth, the anterior margin slightly excavated 

 between the bases of the pollex and dactylus, and bordered there with a 

 short row of- small tubercles. On the median portion of the palm there are 

 two punctures, marking it off into thirds longitudinally. Lateral mar- 

 gins of the manus acute, closely, finely and regularly crenulate ; the lower 

 margin straight, with a row of punctures along the inner side but extremely 

 near the edge, and another less close to the edge outwardly ; upper margin 

 deeply curved clown posteriorly, produced into a deflexed lobe, and simi- 

 larly margined with spaced punctures. Pollex about one-half the total 

 length of the palm, curved at the tip, having a blunt median tooth and 

 a crenulated ridge on the grasping face, the lateral edges of which are 

 smooth except at their bases which are crenulated. The dactylus has two 

 contiguous, crenulated ridges along the outer edge. 



Carpus is somewhat shorter than the palm, equally convex on both sides, 

 with sharp, crenulated edges like the manus ; more swollen distally. The 

 lower distal angle is acute, and there is an oblique groove and a short keel 

 bordered with small tubercles near it on the outer face. The upper proxi- 

 mal angle is produced backward. The inner face has a small distal group 

 of tubercles and some scattered pustules, both usually almost effaced. 



Merus subtriangular in section, the upper keel strongly arched, lower 

 keel nearly straight and more strongly serrate, the middle of the very 

 convex outer surface granulose, with two rounded tubercles at the anterior 

 extremity ; the opposite or inner face nearly flat. In all specimens pre- 

 served with the members in place, the merus is flexed at a right angle with 

 the carpus. 



