370 CRUSTACEA 



G. fasciatus Say (Fig\ 583). First and second antennae of about 

 the same length; length 15 mm.; color whitish: common in fresh-water 

 ponds and streams, it and Hyalella dentata being the common fresh-water 

 amphipods in the eastern states. 



2. Carinogammarus Stebbing-. Telson deeply cleft; last 3 abdom- 

 inal segments with bunches of small hairs and first 3 each wdth a dorsal 

 backwards projecting spine: about 9 species. 



C. mucronatus (Say) (Fig. 584). Antennae of the same length; 

 length 15 mm.; color greenish: Cape Cod to Florida, common among 

 algae and in brackish water. 



Fig. 584 Fig. 585 



Fig. 584 — Carinogammarus mucronatus (Paulmeier). Fig. 585 — EJasmopus l<evis 



(Paiilmeier). 



3. Elasmopus Costa. First antennae twice as long as the second; 

 first 3 abdominal segments veiy large, last 3 small and bent beneath 

 them: about 9 species. 



E. laevis (S. I. Smith) (Fig. 585). Last 3 pairs of abdominal ap- 

 pendages short and thick ; length 10 mm. ; color brownish ; first gnathopods 

 small, second large: Cape Cod to New Jersey, under rocks and among 

 seaweeds near low-tide mark. 



Family 6. PHOTIDAE. 



First antennae with or without a small secondary flagellum and longer 

 than the second; mandible with a long palp; second gnathopods larger 

 than the first: 10 genera and about 40 species. 



Leptocheirus Zaddach {Ptilocheirus Stimpson). Terminal pleopods 

 biramose; both pairs of gnathopods large and chelate; first antennae with 

 a minute secondary flagellum: 8 species. 



L. pingius Stim. Body thick, and variegated in color; length .13 

 mm.: New Jersey to Labrador; common on muddy bottoms. 



