MARINE GAMMARIDEAN AMPHIPODA 225 



Eusirella Chevreux 



Eusirella Chevreux, 1908b. 



Type-species: E. elegans Chevreux, 1908b (original designation). 



Accessory flagelliim absent; mandibular molar not triturative; [lower 

 lip unknoAvn] ; palp oj maxilla 1 short, article 1 much longer than article 

 2j gnathopods not eusirid, scarcely subchelate but article 6 not 

 fully linear, article 5 not or scarcely lobate, shorter than article 6; 

 pereopods 1 and 2 with article 6 hearing long plumose posterior setae; 

 pereopods 3-5 with articles 4-6 each longer than article 2. Species: 

 4, cosmopolitan, bathypelagic. 



Eusirogenes Stebbing 



Eusirogenes Stebbing, 1904. 



Type-species: E. dolichocarpus Stebbing, 1904 (monotypy). 



Accessory flagellum articulate, very long; lower lip with inner 

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

 gnathopods eusirid, subchelate, articles 4-6 each not longer than 

 article 2; palp article 3 of mandible shorter than article 2 {Eusirus, 

 Pareusirogenes) ; antennae lacking calceoli (Eusiropsis) ; article 6 oj 

 gnathopod 1 larger than that oj gnathopod 2. Species: 5, cosmopolitan 

 (N. Hemisphere), bathypelagic. 



Eusiroides Stebbing 



Eusiroides Stebbing, 1888; 1906. 



Type-species: Atylus monoculoides Haswell, 1880c (indicated by 

 Delia Valle, 1893, through erroneous synonymy and thus by synonymy 

 of Stebbing, 1906, but firmly selected by Chevreux and Fage, 1925). 



Accessory flagellum articulate, of medium size; lower lip with small 

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

 gnathopods not eusirid, subchelate, article 5 lobate, shorter than 

 article 6, palms armed with very stout spines; pereopods 3-5 with 

 articles 4-6 each not longer than article 2. Species: ca. 6, ?cosmo- 

 politan, littoral to ?bathyal. 



Eusiropsis Stebbing 



Eusiropsis Stebbing, 1897; 1906. 



Type-species: E. riisei Stebbing, 1897 (monotypy). 



Accessory flagellum articulate, minute; mandibular molar not trit- 

 urative; lower lip with inner lobes; inner plate of maxilla 1 with four 

 or fewer termijaal setae; gnathopods eusirid, articles 4-6 touching; 

 pereopods 3-5 with articles 4-6 each much longer than article 2; 

 antennae with calceoli (Eusirus, Eusirogenes, Pareusirogenes). Species: 

 1, S. Hemisphere (?cosmopolitan), bathypelagic. 



