44B APPENDIX TO CRUSTACEA [December, 



2, C. mercenaria^. Thorax subequal, about four la- 

 teral very obtuse teeth; clypeus with a fissure, lateral seg 

 ments three- iobed; fingers black at tip. 



Inhabits the southern states. 



Cabinet of the Academy. 



Body maculated when recent; thorax each side di- 

 vided by tour sinusses into four veiy obtuse teeth, which 

 are rectilinear at tip and hardly prominent beyond the 

 thoracic curve, cheeks and sides not distinctly granulat- 

 ed, and destitute of the conic tooth beneath the anterior 

 thoracic one; orbits suborbicular, no distinct sinus at the 

 posterior canthus, inferior lid entire and simply concave 

 in the middle of the edge, a profound fissure in the ante- 

 rior canthus; clypeus unequal, an indented fissure in the 

 middle, the lateral segments somewhat three-lobed, an- 

 terior one most prominent; labrum not prominent in the 

 mi^dlt'y pectus of the male with a hispid fascicle on 

 the second and third segments each side; carpus within 

 dilated into a very obtuse, obliquely compressed tooth, 

 beneath which there is no angle; hands unequal, rounded 

 above and beneath; fingers black, at base colour of the 

 hand, teeth obtuse; tibia of the remaining feet fascicu- 

 late above and beneath with rigid hairs and punctured 

 each side; tarsi densely hirsute above and beneath, a 

 longitudinal fascicle each side at base, tips glabrous; ab- 

 domen of the male, second segment hardly narrower than 

 the preceding, third segment hardly wider than the next, 

 convex each side, lateral edge regularly rounded, penul- 

 timate segment slightly wider at tip than the base of 

 the terminal segment, ultimate insisure nearly rectilinear 

 or but slightly curved. 



