GAMMARIDEAN AMPHIPODA 187 



Lysianopsis (?) dissimilis: Hurley, 1963, pp. 76-77, fig. 2 Id. 



This species was collected originally by Stout from kelp holdfasts 

 at Laguna Beach, California; apparently it does not inhabit the 

 intertidal zone of that area and it is very scarce at Corona del Mar 

 and La Jolla on either side. Instead, L. macromerus has been found 

 to predominate in the intertidal of southern California. At first, 

 L. pariter, a new species, was believed to be A. dissimilis. There are 

 few identifying clues in the description given by Stout, but Shoe- 

 maker (1942b) redescribed A. dissimilis from Bahia Magdalena, 700 

 miles to the south. Specimens similar to his are at hand from Bahia 

 de Los Angeles in the Gulf of California and from Pt. Conception, 

 California, in a depth of about 18 meters. That Shoemaker's specimens 

 represent what Stout described is supported by Stout's description 

 of a biarticulate outer ramus of uropod 3 slightly exceeding the 

 length of the inner ramus. This would eliminate L. pariter from con- 

 sideration as Stout's species, even though she placed A. dissimilis 

 originally in the genus Nannonyx Sars. The inner ramus of uropod 

 3 of Nannonyx and of L. pariter is significantly shorter than the 

 outer ramus and the peduncle is more strongly expanded than in 

 A. dissimilis. 



That Shoemaker (1916) in his erection of Aruga macromerus also 

 was not describing Nannonyx dissimilis Stout is shown in the uniar- 

 ticulate outer ramus of uropod 3 ; otherwise there is nothing in Stout's 

 meagre description to distinguish the two species. 



Material. — goleta: Macrocystis holdfast, 3 m., rare. pt. dume: 

 Amaroucium sp., scarce; loose rocks, rare, corona del mar: tunicate 

 colonies at base of Phyllospadix leaves, moderately abundant; tuni- 

 cates and soft polychaete tubes, rare, la jolla : Phyllospadix-corallme 

 grid, scarce (11 per sq. m.). 



Distribution. — Pt. Conception, California, southward to the tip 

 of Baja California, and in the Gulf of California at Bahia de Los 

 Angeles, 0-41 m. A moderately rare species, possibly associated 

 with tunicates or sponges, but several gut analyses of the amphipod 

 show contents of sand and silt particles. 



Lysinnassa macromerus (Shoemaker), new combination 



Figures 48, 49 



Aruga macromerus Shoemaker, 1916, pp. 157-158. — Gurjanova, 1962, pp. 296-297. 

 Lysianopsis (?) macromerus Hurley, 1963, p. 77. 



Diagnosis. — Epistome lamellar, produced forward as keel slightly 

 exceeding rather short plate of upper lip, notch between epistome and 

 upper lip rather short for genus; mandibular palp attached proximal 

 to molar but not as proximallv as in most members of genus; inner 

 plate of maxilla 1 with one long distal seta, outer plate with primary 



