ORDER AMPHIPODA — HYPERIA. 39 
Genus Hyrerra, Latreille. Body subconical, short. Head moderately large, round and pointed in 
front. Antenne short and setaceous. Feet simple, terminating in a slender point, and sub- 
equal. Three first rings of the abdomen very large; the four following very small, and 
forming a sort of caudal fin furnished laterally with three pair of long and slender appendices, 
each terminating in two very minute lanceolated plates. Parasitic. 
Hf. latreilli. (Epw. An. Se. Nat. Vol. 20, p. 388. Say, Lanceola pelagica, Ac. 8c. Vol. 1, p. 318. 
Goutp? loc. cit. p. 335.) Anterior pair of feet shortest; third, fourth and seventh equal; fifth 
longer; sixth longer than the thorax. This species is probably the same noticed by Dr. Gould 
under the name of H. galba, Mont., as occurring in the pouches of the Medusa , on the coast 
of Massachusetts. Mr. Say’s specimen was obtained from the Gulf stream. 
Genus Popocerus, Leach. Antenne pediform; the lower longest and much more robust, with the 
terminal joint inarticulate or obscurely jointed. The two anterior pairs of feet monodactyle; 
hands dilated; those of the second pair largest, the palms unarmed. Allied to Corophiwm. 
P. cylindricus. (Sav, Jour. Acad, Nat. Sc. Vol. 1, p. 387.) Hands of the second pair not larger than 
the carpus, somewhat cylindrical; third, fourth and fifth pairs of feet short, much compressed. 
Eyes small, not prominent. Length, 0°15. Hab. seaweed. Egg harbor, New-Jersey. 
