MARINE GAMMARIDEAN AMPHIPODA 331 



A. edwardsii as type of Onisimus, erroneously, and I follow his prece- 

 dent in using A. edwardsii as type of Boeckosimus. Gurjanova (1951) 

 listed Anonyx plautus Kr0yer, 1845, as type of Onisimus but this 

 is also erroneous. The genus Alihrotus Milne Edwards, 1840, may 

 be a senior synonym either of Boeckosimus or Onisimus but its status 

 has remained unclear. Stebbing (1906) lists it as a dubious genus. 

 Its type-species, Lysianassa chauseica Milne Edwards, 1830 (mono- 

 typy), probably cannot be a member of either Onisimus {=Pseudali- 

 hrotus) or Boeckosimus { = "Onisimus" auct.) because no species of 

 either genus has been recorded as far south as Isles Chauseay in the 

 EngUsh Channel. 



Upper lip and epistome not prominent; mandibular molar ridged 

 (Anonyx), palp attached level with molar; gnathopod 1 subchelate or 

 poorly subchelate, articles 5 and 6 subequal or article 6 longer than 

 5; inner ramus of uropod 2 constricted or not; telson short (Hippome- 

 don), variable, entire or cleft one third; outer plate of maxilla 1 with 

 nine or more spines; palp of maxilliped elongate and slender, outer 

 plate of maxilliped reaching to end of palp article 2 (Rifcus) . Species : 

 16, arctic-boreal, mostly N. Atlantic, littoral to abyssal. 



Note: This genus {^'Onisimus'' auct.) and Onisimus (=Pseudali- 

 brotus auct.) are very close. Sars (1895) distinguished them on the 

 more powerful gnathopod 1 and uropod 3 and longer antennae of 

 "Pseudalibrotus" and Gurjanova (1962) distinguished them on the 

 absence of bent spines on the apices of the maxillipedal outer plates 

 in "Pseudalibrotus." Most species of ''Onisimus" have slightly cleft 

 telsons and various species of "Pseudalibrotus'' have the epistomal 

 portion of the prebuccal complex dominating the labral portion. 

 All of these seem to be very weak generic characters. If the genera 

 were synonymized the unfortunate nomenclatural problems would be 

 solved. 



Cebocaris J. L. Barnard 



Cehocaris J. L. Barnard, 1964a. 



Type-species: C. grutesca J. L. Barnard, 1964a (original designa- 

 tion) . 



Epistome large, broad, convex, but not projecting beyond upper 

 lip from lateral view; head deformed; mandibular molar absent; 

 gnathopod 1 simple, articles 5 and 6 subequal; article 5 of gnathopod 2 

 only slightly longer than article 6, appendage simple; coxae 1 and 2 

 small, but coxa 3 only slightly enlarged and covering coxa 2 only 

 partially; article 2 of pereopod 3 not indentured; pereopods 1-5 

 strongly prehensile; telson short, entire. Species: 1, Caribbean, 

 abyssopelagic. 



285-135 O - 69 - 22 



