MARLN'E GAMMARIDEAN AMPHIPODA 439 



Some Stenothoidae lack a mandibular palp and all have a shield- 

 like coxa 4 but the first coxa is always very small and hidden by the 

 second coxa and the accessory flagellum is a vestigial scale or absent. 



The Ami)hilochidae have a small coxa 1 partially hidden by follow- 

 ing coxae and the mouthparts project in a quadrate bundle. 



The general asi:)ect, head, coxae, body shape, mouthpart bundle, 

 telson, uroj^ods, pereopods, and gnathopods of Stegocephalidae suggest 

 affinities \\'ith the Acanthonotozomatidae but the absence of mandib- 

 ular palps and molars and the elytriform mandibular bod}^ distin- 

 guish the Stegocephalidae. 



Stegocephalidae have considerable resemblance to Lysianassidae. 

 Some stegocephalid species have an elongate article 3 on gnathopod 

 2 which resembles that of those Lysianassidae having gnathopod 2 

 simple (not subchelate). However, most lysianassids have a mitten- 

 shaped or minutely chelate article 6. All Stegocephalidae lack mandib- 

 ular paljDs and molars, have some foliaceous portions on the maxillae, 

 have a 1- or 2-articulate accessory flagellum and a highly characteristic 

 configuration of coxae 1-4. This combination of characters never 

 occurs in Lysianassidae. 



Andaniotes ingens Chevreux (1906c) probably should form the type 

 of a new genus because of its reduced first maxillary palp and narrow 

 article 2 of pereopod 4 in combination but in other special characters 

 it fits Euandania more than Andaniotes and so is transferred to the 

 former. Andaniotes simplex K. H. Barnard (1930) also should be 

 distinguished as a new genus by its 3-, not 4-articulate maxillipedal 

 palp, having articles 1 and 2 coalesced. 



Key to the Genera of Stegocephalidae 



1. Mandible bearing multi toothed (often minutely) incisor (fig. 160/) ... 2 

 Mandible bearing smooth incisor (fig. 160^') 14 



2. Telson cleft (fig. 161z) 3 



Telson entire (fig. 161i) 11 



3. Maxilla 2 lacking outer plate Bathystegocephalus 



Maxilla 2 bearing outer plate 4 



4. Palp article 2 of maxilliped produced distomedially (fig. 161e) . . Phippsia 

 Palp article 2 of maxilliped not produced 5 



5. Palp of maxilla 1 biarticulate (figs. lQOi,k) 6 



Palp of maxilla 1 uniarticulate (fig. 160j) 8 



6. Article 2 of pereopod 4 broad (fig. 1610 7 



Article 2 of pereopod 4 slender (fig. 16U) Stegocephalopsis 



7. Outer plate of maxilla 2 gaping and geniculate (figs. 161o, 6, c) . . Phippsiella 

 Outer plate of maxilla 2 normal (fig. 161 rf) Pseudandaniexis ' 



8. Article 2 of pereopod 4 slender (fig. 161 A) 9 



Article2of pereopod 4 broad (fig. 1610 10 



Telson unknown. 



