46 BULLETIN 138^ UNITED STATES NATIONAL MUSEUM 



margins short, dentate, postero-lateral margins convergent. Cheli- 

 pecls stout. Ambulatory legs long, slender, compressed. Abdomen 

 at base covers sternum between last pair of legs. 

 Eocene; Oligocene; Pliocene. 



COELOMA MARTINEZENSIS. new species 



Plate 11, figs. 1-3 



Description. — The hexagonal carapace (pi. 11, fig. 2) is wider 

 across the front and orbits than along the posterior margin, the 

 postero-lateral margins being strongly conA^ergent ; the antero-lateral 

 margin is about two-thirds as long as the postero-lateral. The 

 gastric region is narrow, only one-third as wide as the carapace and 

 is separated by a wide and deep furrow from the branchio-hepatic 

 regions. Hepatic regions mostly swollen, defined posteriorly by a 

 sinuous furrow running inward from behind the second lateral 

 tooth, and by a pit half way betAveen the end of that furrow and 

 the gastric margin. The greater part of the branchial region is 

 moderately SAVollen, a depressed area both in front of and behind 

 the swelling. A deep median furrow proceeds from the mesogastric 

 region to the edge of the front, while a shallower furrow embraces 

 the inner part of the orbital region. The surface is covered with 

 rather close set, prominent and unequal granules. 



The front is less than one-third as wide as the fronto-orbital dis- 

 tance, it is deflexed, deeply bilobed, each lobe itself bilobed, but the 

 exact shape of these lobules is obscure. The upper border of the 

 broad orbit is directed slightly forward toward the outer tooth and 

 shows distinctly two emarginations, between and behind which there 

 is a small, triangular depressed area. The outer tooth points directly 

 forward, its outer margin is longer than its inner, the next two teeth 

 on the lateral margin are directed obliquely outward; tliese three 

 teeth are nearly triangular with subacute tips; fourth or last tooth 

 directed outward, tips broken off. 



Chelipeds very unequal, the right the larger; merus joints project- 

 ing little beyond carapace; carpus broader than long, inner angle 

 prolonged in a tooth or spine, outer angle blunt and rather promi- 

 nent, upper surface covered with reticulating ridges. The larger 

 palm (pi. 11, fig. 3) is very thick and very little longer, measured 

 on its middle distance, than the fingers ; it Avidens from the proximal 

 to the distal end, the upper edge very convex, the lower sinuous to 

 end of finger ; lower third of outer surface of manus and also finger 

 flat; remainder of manus very convex especially in a vertical direc- 

 tion. The propodal finger has a broad, basal half, its prehensile edge 

 shows seven lobes, its thick tip is upcurved. The dactylus is curved, 

 but may have fitted the immovable finger when closed against it, 



