510 THE AMERICAN NATURALIST. [Vor. XXXIV. 
A’. Postorbital projection an obtuse lobe . . . . P. dalli Rathbun, D 
Genus Chioncecetes Krgyer. 
Key to Species. 
A. Carapace tuberculous ; branchial reiss flattened 
C. opilio (O. Fabricius), WA 
A’, Carapace spinous ; branchial regions dilated 
C. tanneri Rathbun,! APD 
Genus Pelia Bell. 
Key to Species. 
A. Hands in male with margins tapering to the fingers, which have their 
edges meeting throughout . . P. pacifica A. Milne-Edwards, D 
Fic. 4. — Chioneecetes tanneri. 
A’, Hands in male with margins subparallel; fingers gaping at base 
P. mutica (Gibbes), MSG 
Genus Hyas Leach. 
Key to Species. 
A. Carapace subtriangular ; VERUR region not dilated laterally. Basal 
antennal joint subtriangular . H. araneus (Linneus), V 
A’. Carapace lyrate; hepatic region dilated laterally. Basal antennal 
joint with sides nearly parallel. 
B. Posterior angle of hepatic projection rounded. Basal antennal 
joint without a large tubercle at the antero-external angle i 
H. coarctatus Leach, NMA 
B'. Posterior angle of hepatic projection subacute. Basal antennal 
joint with a large tubercle at the antero-external angle 
H. lyratus Dana, AP 
Genus Nibilia A. Milne-Edwards 
AV. erinacea A. Milne-Edwards, M( CH )C 
Genus Seyra Dama... — . . . S. acutifrons Dana, APD 
Genus Chorilia Dana. . . . . . . . . . C. Zengipes Dana, APD 
* Only in exceptional has thi ies been found above the 100-fathom line. 
