MARINE GAMMARIDEAN AMPHIPODA 405 



Princaxelia Dahl 



Princaxelia Dahl, 1959. 



Type-species: P. stephenseni Dahl, 1959 (original designation). 



Article 2 of antenna 1 shorter than article 1; upper lip scarcely 

 incised, lobes slightly asymmetrical; [lower lip unknown]; maxillipedal 

 palp more than three times as long as medial edge of outer plate {Par- 

 dalisca); gnathopods simple, article 5 longer than 6, dactyls simple; 

 telson deeply cleft. Species: 2, N. Atlantic, S. W. Pacific, bathyal 

 to hadal. 



Phliantidae, revised 



[see J. L. Barnard, 1964c] 

 Figures 145-147 



Diagnosis. — Accessory flagellum absent; body dorsally depressed, 

 at least anterior coxae splayed; mandible lacking palp, molar degraded; 

 palp of maxilla 1 degraded or absent; gnathopods feeble; usually 

 uropod 3 lacking inner ramus, often lacking both rami. See Prophli- 

 antidae, Eophliantidae, Kuriidae, Dogielinotidae, Talitroidea, Dex- 

 aminidae, Pagetinidae, Acanthonotozomatidae, Colomastigidae, 

 Cressidae. 



Description. — Phliantidae are depressed dorsally, except Phlias 

 which is "compressed" (Stebbing, 1906), with pleon flexed below re- 

 mainder of body, segments armored and coxae projecting laterally; 

 accessory flagellum absent; mandible lacking palp, molar absent or 

 represented by a smooth protuberance or spine; lower lip with or 

 without inner lobes; maxilla 1 with degraded palp, 1-articulate or 

 represented by a spine when present; maxilla 2 small, often with 

 coalesced lobes; plates of maxilliped well developed, palp 2- to 4- 

 articulate; gnathopods feeble, usually simple, but subchelate in genera 

 Plioplateia and Ceina, article 3 of gnathopod 2 elongate; uropod 1 

 biramous (except Temnophlias) , uropod 2 usually biramous (except 

 Temnophlias and Pereionotus) , uropod 3 uniramous in most genera 

 or rami absent; telson usually entire (or cleft in Ceina). 



Some students, particularly Chevreux (1911a) have considered that 

 uropod 2 is missing in Pereionotus and that the last biramous uropod 

 in that genus is uropod 3. However, Pereionotus as stated by Stebbing 

 (1906) probably has a small uropod 3 lacking rami, perhaps over- 

 looked by Chevreux. Uropod 3 has not been clearly described in some 

 genera (especially Ceina). 



Relationship. — ^The Prophliantidae have biramous third uropods, 

 a cleft telson, and often have a degraded flagellum on antenna 2. 



