GAMMARIDEAN AMPHIPODA 



189 



Figure 49. — Lysianassa macromerus (Shoemaker), female, 5.0 mm., station 39-K^i: a, 

 pereopod 2; b, uropod 1; c, uropod 2; d, uropod 3; e, telson. 



dimensions (not shortened as in Arugella heterodonta Pirlot) ; gnathopod 

 2 chelate; a large striated spine present on posterodistal end of article 

 6 of pereopods 1-2; pereopods 3-5 rather short, second articles un- 

 usually asymmetrical and broad, fourth articles broad, each with 

 long posterior process nearly reaching end of article 5; article 5 about 

 half as long as article 6; pleonal epimera 1-2 each with small tooth 

 at posteroventral corner, third epimeron slightly convex posteriorly, 

 rounded-quadrate at ventral corner, epimeron not prolonged posteri- 

 orly as in Aruga oculata Holmes; inner ramus of uropod 2 with marginal 

 constriction; uropod 3 short, peduncle scarcely lamelliform, outer 

 ramus equal to peduncle in length, uniarticulate, inner ramus about 

 two thirds as long as outer ramus; telson entire, slightly convex 

 apically. 



Material. — cayucos: Phyllospadix-peivetiid grid, rare (6 per sq. 

 m.). hazard canyon: algal turf on platform, rare (6 per sq. m.). 

 goleta: Phyllospadix-peivetiid grid, second most abundant species 

 (1588 per sq. m.). pt. dume: short brown algae, fourth most abundant 

 species (1020 per sq. m.); coralline algae, fifth most abundant species 

 (1285 per sq. m.) ; pelvetiids, scarce (18 per sq. m.) ; short greenish 

 brown algae, fourth most abundant species (176 per sq. m.); Phrag- 

 matopoma masses, scarce (73 per sq. m.); loose rocks, most abundant 

 species; Egregia holdfasts, second most abundant species; in bed of 

 Aiithopleura elegantissima, very abundant, corona del mar: Phyl- 

 lospadix-cor&Hine grid, scarce (28 per sq. m.) ; loose rocks, moderately 

 abundant, la jolla: sand-inundated algae at high tide line, fifth 

 most abundant species (367 per sq. m.). 



Distribution. — Cayucos, California, to La Jolla, especially abun- 

 dant in harsh environments as at Pt. Dume and Goleta and in sand- 

 inundated algae at high tide line as at La Jolla. 



