236 U.S. NATIONAL MUSEUM BULLETIN 271 



29. Eyes four in number; inner plate of maxilla 1 with medial edge fully lined 



with setae Quadrivisio 



Eyes two in number; inner plate of maxilla 1 with only terminal setae. 



Paraceradocus 



30. Maxilla 2, medial edge of inner plate not lined with setae 31 



Maxilla 2, medial edge of inner plate lined with setae 33 



31. Palp of maxilliped with three articles Maerella 



Palp of maxilliped with four articles 32 



32. Mandibular palp article 3 stout, falcate (fig. 95e) Elasmopus 



Mandibular palp article 3 slender, not falcate Maera 



33. Palm and posterior margin of article 6 on gnathopod 2 not distinct from one 



another (fig. 951), article 7 of gnathopod 2 nearly as long as article 6, 



rami of vu'opod 3 equal to peduncle in length Gammarella 



These characters not combined 34 



34. Lower lip lacking inner lobes 35 



Lower lip bearing inner lobes (presumptive in Ceradocoides and Maera- 



cunha) 36 



35. Mandibular palp article 3 naked on medial edge, dactyl of maxilliped about 



75% as long as article 3, claw-shaped, coxa 4 not excavate posteriorly. 



Ceradocopsis 



Mandibular palp article 3. satose medially, dactyl of maxilliped 25% as long 



as article 3, setose, coxa 4 excavate posteriorly .... Bathyceradocus 



36. Maxilla 1, medial edge of inner lobe not lined with setae 37 



Maxilla 1, medial edge of inner lobe lined with setae 38 



37. Outer ramus of uropod 3 bearing minute article 2 Maeracunha 



Outer ramus of uropod 3 lacking article 2 Maeropsis 



38. Uropod 3 with 2-articulate outer ramus 39 



Uropod 3 with 1-articulate outer ramus 40 



39. Mandibular palp article 3 subequal to article 1, bearing only two setae. 



Maeracunha 

 Mandibular palp article 3 slightly longer than article 1, multisetose. 



Metaceradocoides 



40. Male gnathopod 2 very small and slender Metaceradocus 



Male gnathopod 2 enlarged (fig. 95o) 41 



41. Mandibular palp article 3 as long as article 2, slightly sickle-shaped, article 1 



simple Elasmopoides 



Mandibular palp article 3 less than 75% and generally half or less as long 

 as article 2, article 1 with distomedial process or spines. 



Ceradocus and Ceradocoides ^ 



» Not clearly described. 



Genera of Marine Gammaridae 



The term "normal gnathopods" indicates that both pairs of 

 gnathopods are subchelate and gnathopod 2 is larger than 1 in the 

 male. 



Anelasmopus Oliveira 



Anelasmopus Oliveira, 1953. 



Type-species: A. kraui Oliveira, 1953 (monotypy). 



