GAMMARIDEAN AMPHIPODA 121 



Elasmopus rapax serricatus, new subspecies 



Figure 24 j-m 



Diagnosis of male. — Accessory flagellum uni- or biarticidate; no 

 body segments dorsally toothed; gnathopod 2 with oblique palm 

 not distinct from posterior margin of article 6, strongly setose its full 

 length adjacent to simple, large hinge process; middle palmar tooth 

 situated just proximal to hinge process, truncate, lamellar, often 

 transparent and difficult to see among dense setae; palm defined by 

 small ridge bearing one spine and also difficult to see; second articles of 

 pereopods 3-4 closely serrate posteriorly, poorly setose, article 2 of 

 pereopod 5 strongly crenuloserrate (as in E. pectenicrus [Bate]) ; 

 pereopodal dactyls moderately to strongly constricted distomedially ; 

 third pleonal epimeron like E. rapax mutatus, slightly convex pos- 

 teriorly, posteroventral corner rounded-quadrate, posterior edge very 

 sparsely and minutely serrate; inner ramus of uropod 3 shorter and 

 narrower than outer (as in E. rapax mutatus) ; telson short, with 

 truncate apices armed with 5-8 spines (4 in juveniles). Female with 

 small gnathopod 2, see figure. 



Holotype — AHF No. 632, male, 8.0 mm. 



Type locality. — Station 45-K-l, La Jolla, California, Novem- 

 ber 11-13, 1962, wash of Phyllospadix sp. on second ridge from sea. 



Relationship.- — The preceding diagnostic keys show the relation- 

 ship of this subspecies. It differs from E. rapax mutatus in its strongly 

 crenuloserrate fifth pereopod which develops by increments from a 

 strongly serrate condition in the young, similar to E. rapax mutatus. 

 Young individuals may be identified by the truncate telsonic apices 

 having at least 4 spines. Adults of more than one species of Elasmopus 

 rarely occur in the survey samples; where so occurring, juveniles 

 have not been specifically identified but for counting purposes split 

 in proportion to adult frequency. 



Material.- — carmel: Egregia stipes, second most abundant species. 

 pt. dume: short-tufted brown algae on vertical ledge face, scarce (14 

 per sq. m.). corona del mar: Phyllospadix-cor&Mme grid, scarce (38 + 

 per sq. m.); loose rocks, scarce; red-brown algae below water, mod- 

 erately abundant; tunicates and soft polychaete tubes, scarce, la 

 jolla: Phyllospadix-corsbllme grid, third most abundant species (1714 

 per sq. m.); underrock grid, most abundant species (293 per sq. m.); 

 short-tufted red algae, abundant (988+ per sq. m.) ; coralline algae, 

 abundant; mixed red algae in tidepool, abundant. 



Maera inaequipes (Costa) 



Maera inaequipes (Costa) : J. L. Barnard, 1959, pp. 25-26, pi. 5. 



Positive identification of this Californian taxon will require com- 

 parison of growth stages with European topotypical populations. 



