394 REPORT OF NEW JERSEY STATE MUSEUM. 



Key to the genera. 



a. Ridges defining efferent branchial channels, if present, low and confined 

 to hind part of endostome, never reaching to front boundary of buccal 

 cavern. 



b. Carapace transversely oval. EURypanopeus 



hb. Carapace more or less hexagonal or subquadrate. 



c. Terminal abdominal segment of male long; carapace subquadrate, 



narrow (length about three-fourths width) ; prominent transverse 



dorsal ridges. rhithropanopeus 



cc. Terminal abdominal segment of male subtriangular ; carapace, when 



subquadrate, wider than in preceding. 



d. Front arcuate ; carapace hexagonal. neopanopE 



- dd. Front with truncate or sinuous lobes. 



[e. Front very narrow and advanced; postero-lateral margins 



strongly converging ; carapace hexagonal, hexapanopeus] 



ee. Front moderately wide ; postero-lateral margins not 



strongly converging; carapace subquadrate. eupanopeus 



aa. Ridges defining efferent branchial channels extending to front boundary 



of buccal cavern, often very strong. Eurytium 



Genus EURYPANOPEUS A. Milne-Edwards. 



Eurypanopciis A. Milne-Edwards, Miss. Sci. Mex. Crust., V, 1878, p. 318. 

 Type Panopeus crenatits Milne-Edwards, first species. 



Carapace transversely oval. Fronto-orbital border half or 

 more than half greatest width of carapace. Chelipeds without a 

 circular cavity on front edge. Four antero-lateral teeth besides 

 orbital, first of which low and more or less fused with orbital. 

 Carpal joints of ambulatory legs not armed with a horned crest. 

 Ambulatory legs not spiny nor granular on upper border. 



One species in our region. 



Eurypanopeus depressus (S. I. Smith). 



Plates 117 and 118. 



Mud Crab. 



Panopeus depressus S. I. Smith, Proc. Boston Soc. N. Hist., XII, 1869, p. 

 283. Nezv Haven, Connecticut. Egmont Key, Florida. 



(S. I. Smith) Verrill, Rep. U. S. F. Com., I, 1871-72 (1873), p. 312, 



PI. I, fig. 3 (under stones in muddy places; extending to Florida or 

 the Gulf coast of Southern States, rare north of Cape Cod). 



