258 U.S. NATIONAL MUSEUM BULLETIN 271 



Type-species: P. zimmeri Schellenberg, 1931 (monotypy). 



Antenna 1 not geniculate; mandibular palp on basal process, large, 

 article 3 clavate (Urothoe, Urothoides), molar ridged; outer plates of 

 maxilla 2 not enlarged; maxillipedal palp 4-articulate; coxa 1 nearly 

 obtusely pointed below, others rounded-quadrate; gnathopods sub- 

 chelate or nearly simple, article 5 of gnathopod 1 longer than article 

 6; pereopods dactylate; uropod 3 short, rami subfoliaceous, subequal 

 in length; telson short, deeply cleft. Species: 2, subantarctic-anti- 

 boreal, littoral. 



Platyischnopus Stebbing 



Platyischnopus Stebbing, 1888; 1906. 



Type-species: P. mirabilis Stebbing, 1888 (monotypy). 



Antenna 1 not geniculate; mandibular palp not on basal process, 

 molar "ridged," smooth or absent; outer plates of maxilla 2 not 

 enlarged; maxillipedal palp 4-articulate; coxae of medium length, 

 rounded-quadrate below; gnathopods chelate, article 5 of gnathopod 



1 longer or shorter than article 6; pereopods dactylate; uropod 3 

 (outer ramus only) immensely elongate, inner ramus short, scale-like ; 

 telson partially cleft or emarginate; head with "shark-nose" rostrum. 

 Species: 6, warm N. temperate through tropics to antiboreal, littoral. 



Pontoporeia Kr0yer 



Pontoporeia Kr0yer, 1842. — Stebbing, 1906. 



Type-species: P. femorata Kr0yer, 1842 (monotypy). See Sars, 

 1895. 



Antenna 1 not geniculate; mandibular palp not on basal process, 

 molar ridged; outer plate of maxilla 2 not enlarged; maxillipedal 

 palp 4-articulate; coxae 1-2 of normal size, rounded-quadrate below; 

 gnathopod 1 subchelate, articles 5-6 subequal in length, gnathopod 



2 slightly chelate; at least pereopods 1, 2, 5 dactylate; rami of uropod 



3 equal in length; telson cleft halfway or more. Species: 5; 1 

 Caspian, 4 subarctic-boreal and glacial relicts, littoral. 



Priscillina Stebbing 



Priscilla Boeck, 1871 (homonym, Coleoptera). 

 Priscillina Stebbing, 1888 (new name); 1906. 



Type-species: Pontoporeia armata Boeck, 1861 (monotypy). See 

 Sars, 1895. 



Antenna 1 not geniculate; mandibular palp not on basal process, 

 molar ridged; outer plate of maxilla 2 not enlarged; maxillipedal 

 palp 4-articulate; coxae 1-2 of normal size, coxae 1-4 obtusely pointed 

 below; gnathopods subchelate, articles 5-6 of gnathopod 1 subequal 



