GAMMARIDEAN AMPHIPODA 169 



Liljeborgia geminata differs from L. marcinabrio J. L. Barnard 

 (1968), from the Gulf of California, by the subcircular, not reniform 

 eyes, the broader second articles of pereopods 3-5, the vestigial dorsal 

 teeth on pleonites 4-5 and in the evenly projecting subapices of each 

 telsonic lobe. 



Material. — goleta: Macrocystis holdfast, 3 m., rare; submerged 

 log, 8 m., rare, velero records: San Pedro Bay, near Los Angeles, 

 California, 18-19 fm.; Tanner Bank, 38 fm.; Santa Cruz Island, 23 

 fm. 



Distribution.- — Goleta, California, to Bahia de San Quintin, Baja 

 California, 3-70 m. 



Lysianassidae 



Fresnillo, new genus 



Diagnosis/ — Mouthparts not distinctly forming conical bundle 

 below head but genus otherwise related to those with this character; 

 upper lip and epistome amalgamated, forming a large, conspicuously 

 setose anterior lamina; mandible lacking molar, palp attached quite 

 proximally, apex of mandibular body with conical projection; lower 

 lip not resolved; maxillae not clearly delineated, apparently rather 

 degenerate (see discussion below) ; inner plates of maxilliped each 

 a conical, unarmed projection, outer plates scarcely more than a 

 broadened, quadrate extension of parent articles, palp triarticulate; 

 accessory flagellum uniarticulate; gnathopod 1 simple; gnathopod 2 

 lacking article 7; uropods 1-2 with inner rami reduced to short 

 styluses; third uropod formed of rugulose peduncle lacking rami; 

 telson entire, elongated; head telescoped into pereonite 1 with eye 

 partially covered by the segment and coxa 1. Generic name masculine, 

 contrived. 



Type species: Fresnillo Jimbriatus , new species. 



Relationship. — This genus and Ocosingo J. L. Barnard (1964a) 

 comprise a pair of genera from the eastern Pacific and northern 

 hemisphere related to the pair of genera Acontiostoma Stebbing 

 and Stomacontion Stebbing from the southern hemisphere. The 

 latter two now appear to be synonymous because of the discovery 

 of intergrading species (see later discussion). The eastern Pacific 

 pair differs from that in the southern hemisphere by the more com- 

 plete reduction of the inner rami of uropods 1-2 and the loss of 

 article 7 on gnathopod 2. Fresnillo differs from Ocosingo in the degen- 

 erate maxillae and the poorly developed outer plates of the maxilliped. 



Acontiostoma Stebbing is presently monotypic while Stomacontion 

 has 5 species, but among those 5 are 2 showing intergradation with 

 Acontiostoma. Stomacontion capense K. H. Barnard (1916) lacks 

 any first maxillary palp, whereas the type species of Acontiostoma 



