238 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



O'. Front arcuate, form- 

 ing a regular curve 

 with antero-lateral 

 margins. Second 

 antero - lateral 

 tooth lobiform, 

 separated from 

 the first by a shal- 

 low sinus. Male 

 abdomen constric- 

 ted between fifth 

 and sixth seg- 

 ments; terminal 

 segment subtrian- 

 gular. 



Neopanope, p. 366. 

 O^. Hexagonal. Front 

 narrow, prominent 

 beyond curve of 

 antero-lateral mar- 

 gins. Postero-lat- 

 eral margins 

 strongly converg- 

 ing. Antero-lat- 

 eral teeth promi- 

 nent. Supra-orb- 

 ital lobe well 

 marked. 

 Hexapanopeus, 



p. 383. 

 A.'. The ridges that define the efferent branchial channels extend to the anterior 

 boundar}' of the buccal cavity and are often very strong. 

 B'. Eyestalks subcylindrical, circular in cross-section. 



C. Fronto-orbital border half or less than half the greatest width of 

 carapace. 

 D'. Basal antennal article does not nearly reach front. 



E^ Carapace broad, suboval. Surface of carapace and chelipeds 



smooth Menippe, p. 472. 



E^. Carapace not much broader than long, subcircular. 



Chelipeds very rough Pilumnoides, p. 534. 



D^. Basal antennal article touching front. 



E'. Anterior margin of merus of outer maxillipeds notched at 

 orifice of efferent branchial channel. Orbits suborbic- 



ular Ozius, p. 539, 



W. Anterior margin of merus of outer maxilliped not notched 

 at orifice of efferent branchial channel. Orbits oblong. 



Eurytium, p. 422. 

 C. Fronto-orbital border much more than half the greatest width of 

 carapace. 

 D'. Fronto-orbital border about two-thirds the greatest width of 

 carapace. Antero-lateral borders shorter than postero- 

 lateral. Front with a narrow outer tooth, spine or lobe, 

 separated by a notch from the superior inner angle of orbit. 

 E'. More or less hairy and generally armed with spines or 

 sharp granules Pilumnus, p. 481. 



