MARINE GAMMARIDEAN AMPHIPODA 365 



Tmetonyx Stebbing 



Hoplonyx Sars, 1895 (homonym, Coleoptera). 

 Tmetonyx Stebbing, 1906 (new name). 



Type-species: Oniscus cicada O. Fabricius, 1780 (original desig- 

 nation). See Sars, 1895. 



This genus was synonymized with Tryphosa by J. L. Barnard, 

 1962d, but Tryphosa must be synonymized with Orchomenella, of 

 which Orchomene is a senior synonym, because Boeck designated as 

 type-species of Tryphosa a taxon later proved to be congeneric with 

 the designated type-species of Orchomenella. The Tryphosa concept is 

 now given the next available name, Tryphosella Bonnier, but Tmet- 

 onyx is reinstated on the condition of coxa 1 to include only its 

 type-species. 



Epistome broadly rounded, upper lip broadly rounded, both pro- 

 jecting together slightly (Anonyx), but separated by distinct notch; 

 mandibular molar subcolumnar, slightly attenuated, apparently 

 mostly setulose and poorly or not ridged, palp attached level with 

 molar; coxa 1 perfectly quadrate, neither expanded nor tapered distally 

 {Anonyx, Tryphosella); gnathopod 1 subchelate, articles 5 and 6 

 subequal in length; telson of medium length, deeply cleft; head oj 

 normal size ( TJristes) ; dactyl oj gnathopod 1 with inner tooth {Anonyx) . 

 Species: 1 or 2, N.E. Atlantic Ocean, littoral to abyssal. 



Trischizostoma Boeck 



Gruerinia Costa, 1853b, 1857 (homonym, Diptera). 

 Trischizostoma Boeck, 1861. — Stebbing, 1906. 

 Guerina Delia Valle, 1893 (new name for Guerinia). 



Type-species: Guerinia nicaeensis Costa, 1853b (monotypy and 

 subsequent synonymy). See Sars, 1895. 



Mouthparts forming a ventral conical bundle, styliform; epistome 

 and upper lip not differentially produced; mandibular molar absent, 

 palp attached about medially; lobes of lower lip sublanceolate, lack- 

 ing mandibular processes; palp of maxilla 1 very short; gnathopod 1 

 very powerful, articles 6 and 7 generally inverted in adult so that 

 article 7 closes on article 6 from below; coxa 1 short, dominated by 

 coxa 2; telson short, entire or cleft to middle; branchiae apparently 

 plaited; eyes enormous. Species: 6, cosmopolitan, bathy-abyssopelagic. 



Tryphosella Bonnier {=^^^Tryphosa^'' auct.) 



Tryphosella Bonnier, 1893 [not Stebbing, 1906]. 

 Tryphosa— Sars, 1895.*— Stebbing, 1906 (not Boeck, 1871). 



*Sars' book is cited herein under the date 1895 but it was printed in parts from 

 1891 to 1895 and the section on Tryphosa was printed in 1891, two years before 

 Bonnier's work. 



