228 U.S. NATIONAL MUSEUM BULLETIN 271 



gnathopods eusirid, articles 4-6 not touching; pereopods 3-5 with 

 articles 4-6 each much longer than article 2; antennal calceoli absent 

 (Eusiropsis); posterior border of gnathopodal article 5 formed of a broad, 

 setose lobe, its width greater than tapered distal end of article 5 (Eusirus). 

 Species: 1, N.W. Pacific, abyssopelagic. 



Pontogeneia Boeck 



Pontogeneia Boeck, 1871. — Stebbing, 1906. 



Type-species: Amphithoe inermis Kr0yer, 1838 (monotypy). See 

 Sars, 1895. 



Accessory flagellum absent; lower lip with small inner lobes; 

 inner plate of maxilla 1 with four or more terminal or subterminal 

 setae; gnathopods not eusirid, article 5 not lobate, slightly longer 

 than article 6; pereopods 3-5 with articles 4-6 each not longer than 

 article 2, article 4 slender (Zaramilla) ; outer lobes of lower lip not 

 broadly separated (Meteusiroides). Species: 25, cosmopolitan, littoral. 



Pontogeneiella Schellenberg 



Pontogeneiella Schellenberg, 1929a. 



Type-species: Atyloides brevicornis Chevreux, 1906a, 1906b (pres- 

 ent selection). 



Accessory flagellum absent; lower lip with inner lobes; inner 

 plate of maxilla 1 densely lined with setae on medial edge; gnathopods 

 not eusirid, subchelate, article 5 not lobate, nearly as long as article 

 6; pereopods 3-5 with articles 4-6 each not longer than article 2, 

 article 4- one third as wide as article 2 {Zaramilla); antennae subequal, 

 coxa 4- strongly excavate posteriorly {Prostebbingia) . Species: 2, 

 antarctic, littoral. 



Pontogeneoides Nicholls 



Pontogeneoides Nicholls, 1938. 



Type-species: P. abyssi Nicholls, 1938 (original designation). 



Accessory flagellum articulate, short; lower lip with small inner 

 lobes; inner plate of maxilla 1 with four or fewer terminal setae; 

 gnathopods not eusirid, subchelate, article 5 lobate on gnathopod 

 2, shorter than article 6, pereopods unknown; telson minutely notched. 

 Species: 2, antarctic, bathyal (480-1,590 m). 



Prostebbingia Schellenberg 



Prostebbingia Schellenberg, 1926a. 



Type-species: Stebbingia gracilis Chevreux, 1912a, 1912b (present 

 selection). 



