MARESPEi GAMMARIDEAN AMPHIPODA 317 



49. Gills plaited (deeply folded), labral lobe slightly dominating epistome. 



Anonyx 

 Gills simple (at most striate), epistome equivalent to or dominating labral 



lobe Tmetonyx (type only) 



Gills simple (at most striate), labral lobe slightly dominating epistome. 



Paronesimus 



Genera of Lysianassidae 



The following characters are not mentioned in the diagnoses unless 

 they have classificatory value; if not mentioned they conform to the 

 typical condition as stated in sequel: gnathopod 2 either minutely 

 chelate or subchelate; maxilla 1 with 2-articulate palp, inner lobe 

 poorly setose; maxilliped with well-developed lobes and 4-articulate 

 palp, the fourth article large and claw-like; coxae 1 or 2 large, visible; 

 uropod 3 of medium length, outer ramus 2-articulate, inner slightly 

 shorter than outer, rami lanceolate ; accessory flagellum multiarticulate ; 

 inner ramus of uropod 2 unconstricted or unnotched; mouthparts not 

 formed into a cone-shaped bundle; pereopod 3, article 2 not deeply 

 indentured. 



Acidostoma Liljeborg 



Acidostoma Liljeborg, 1865. — Stebbing, 1906. 



Type-species: Anonyx ohesus Bate, 1862 (monotypy). See Sars, 

 1895. 



Mouthparts forming a ventral conical bundle, styliform; antenna 

 1 very stout in male; upper lip and epistome continuous; mandible 

 usually lacking molar, small when present, palp attached quite 

 proximally; palp of maxilla 1 vestigial, 1 -articulate, outer plate with 

 hook-like spines; palp of maxUliped scarcely exceeding outer plate, 

 article 4 vestigial; gnathopod 1 simple, article 6 slightly longer than 5; 

 gnathopod 2 lacking article 7; uropod 3 short, outer ramus 1-articulate; 

 telson short, cleft or emarginate. Species: 7, boreal, littoral to 

 bathyal (1,200 m). 



Acontiostoma Stebbing 



Acontiostoma Stebbing, 1888; 1906. 



Type-species: A. marionis Stebbing, 1888 (original designation). 



Mouthparts forming a ventral conical bundle, styliform; mandible 

 lacking molar, palp attached quite proximally; palp of maxilla 1 

 uniarticulate ; maxillipedal palp scarcely exceeding outer plate, article 

 4 very small; gnathopod 1 simple, article 6 slightly longer than 5; 

 coxa 1 projecting over side of head; uropod 3 lacking rami; telson 

 short, entire or emarginate. See Stomacontion for remarks. Species: 

 1, suban tare tic, littoral. 



