212 REPORT OF NEW JERSEY STATE MUSEUM. 



flagellum shorter and of ten to fifteen short compressed joints. 

 First gnathopods in male with carpus produced below into 

 rounded large lobe, distally broadened propodus shorter than 

 carpus, and hind low'er angle produced as large rounded lobe,, 

 with distal edge formed as palm against which dactyl closes, 

 also deep notch between this lobe and base of dactyl. Second 

 gnathopods in male with very large stout propodus, convex 

 palm very oblique and notched short distance within little pro- 

 duced hind angle. In female carpus and propodus without lobes,, 

 though hind edge of former somewhat produced below middle. 

 Second gnathopods of female with oblong propodus rounded 

 below, and minute dactyl on front edge not reaching lower 

 end. Merus and carpus in posterior perseopods swollen in adult 

 male. Rami of first uropods distinctly shorter than peduncle. 

 Rami of second uropods subequal with peduncle. Rami of third 

 uropods much narrower than thick peduncle, and about as long. 

 Telson more or less pointed, narrowly rounded behind, 

 spinulose. Color olive-brown generally. Antennae reddish or 

 reddish-brown. Legs, coxal plates and hind portions of 1x»dy 

 tinged bluish. Length lo mm. 



Remarks. — Distributed along the eastern coast of North 

 America from New Jersey (though it likely ranges southward 

 also) to the Bay of Fundy on the north. It is very common 

 among seaweed, where cast in masses, near the shore or above 

 high-water mark. It appears to seldom occur as far up on the 

 beach as Talitrus, and in the daytime it is more active. It is 

 truly a remarkable leaper, hopping with very great rapidity 

 for a great distance, as compared with its size. In disturbing 

 masses of the seaweed perfect swarms of these beach fleas skip 

 about in all directions. It feeds largely on seaweeds, though 

 will not reject animal food. They are seldom found under 

 masses of drift or seaweeds unless damp, or, if so, is usually 

 buried some distance in the sand. It is a perfectly good swimmer 

 if the occasion necessitates, and is also sometimes strongly 

 attracted to the light. Interesting accounts of this and other 

 species and their phototactic habits are given by Holmes.^ 



^ Amer. Journ. Physiology, V, p. 211. 



