102 



U.S. NATIONAL MUSETTM BULLETIN 271 



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Figure 51. — Corophiidae, pereopods usually glandular; like Isaeidae, Aoridae, Ischyroceri- 



dae, but urosome depressed; uropod 3 almost always uniramous: a, extremes in accessory 



flagellum; b, urosome, left lateral aspect to show depression and occasional fusion of 



segments; c, coxa 4, note lack of posterior excavation [shape highly variable]; d,e,f,g,h, 



variations in uropod 3, usually uniramous [see Isaeidae for distinctions from distantly 



related families]; i,j, extremes in telson. 



Genera with uropod 3 like figs, e and h are probably assignable to Ischyroceridae. Genera 



with enlarged gnathopod 1 are probably assignable to Aoridae, and others, except Corophium, 



are assignable to Isaeidae. Podoceridae have extremely elongated urosomite 1. Colo- 



mastigidae and Eophliantidae have degraded mandibles. 



