312 U.S. NATIONAL MUSEUM BULLETIN 271 



Coxa 1 hemioval or subtriangular (fig. 129c). 



Schisturella [ = Pseudonesimus] 



11. Outer lobe of maxilla 1 degenerate and compressed distally, bearing only 



five or six spines 12 



Outer lobe of maxilla 1 normal, distally bearing seven or more spines . . .13 



12. Apices of maxilla 2 lobes densely setose, with nine or more setae each. 



Neoambasia 



Apices of maxilla 2 lobes sparsely setose, inner with one seta, outer with 



about four setae (fig. 127A:) Adeliella 



13. Medial edge of inner lobe of maxilla 1 fully setose, article 3 of gnathopod 



1 elongate, as long as article 6 Paralicella 



Only distal end of inner lobe of maxilla 1 setose, article 3 of gnathopod 

 1 not elongate 14 



14. Mandibular molar an immense, broad, poorly setulose, girdled lamina 



(fig. 126d), article 1 of antenna 2 enlarged and circular in adults (fig. 124i), 



inner plate of maxilla 1 witli five or more setae Eurythenes 



Mandibular molar of medium or small size, cuboid, subspheroid, or conically 

 laminate, article 1 of antenna 2 not subcircular or enlarged, inner plate of 

 maxilla 1 with three or fewer setae 15 



15. Article 4 of maxillipedal palp vestigial (fig. 128a) Centromedon 



Article 4 of maxillipedal palp not vestigial 16 



16. Mandibular molar very small, sublaminate, conical or sharp, article 6 of 



gnathopod 1 enlarged (fig. 129Z). 



some species now assigned to Cheirimedon 

 Mandibular molar of normal size and cuboidal dimensions, article 6 of gnatho- 

 pod 1 small 17 



17. Outer ramus of uropod 3 uniarticulate, mandibular molar ridged. 



Tryphosoides 



Outer ramus of uropod 3 biarticulate, mandibular molar unridged but 



setulose 18 



18. Epistome from lateral view extending much farther than and projecting 



convexly in front of upper lip (fig. 1250- 



Tryphosella ("Tryphosa" auct. and some species of "Tmetomjx" auct.) 



Epistome small, short, unprojecting, occasionally dominated by upper 



lip (figs. 125gr,n,o) 19 



19. Upper lip and epistome small, inconspicuous (figs. 125o,j). 



some species of Uristes 



Upper lip dominating epistome (fig. I2bn) (head ?large, coxa 1 an elongate 



triangle in type-species, variable in others) Ambasiopsis 



KEY P 



1. Gnathopod 1 subchelate, even minutely 2 



Gnathopod 1 simple 11 



2. Either article 4 or 5 of antenna 2 very tumid (fig. 124fc) 3 



Neither article 4 or 5 of antenna 2 tumid 4 



3. Broad epistomal lobe dominating labrum Microlysias 



Labrum strongly projecting in front of epistome Lysianella 



4. Epistome and upper lip amalgamated even though their parts produced, 



parts not separated by notch (fig. 125fc) 5 



Epistome and upper lip separated by deep notch (figs. 125c,/) 7 



5. Maxillipedal palp 3-articulate, peduncle of uropod 3 elongate, nearly as long 



as pleonitc 4 and peduncles of uropods 1-2 and longer than rami of uro- 

 pod 3 Normanion 



