ISOPODS OF NORTH AMERICA. 



885 



three. The epimera of all the segments are consolidated with the 

 segments. The lateral margins are almost straight and continuous. 



The abdomen is composed of one segment, with lateral sutures at the 

 base, indicating another partly coalesced segment; it tapers to a narrow 

 extremity, the apex of which is emarginate. 



The legs are more or less alike in structure. 



SYNIDOTEA BICUSPIDA (Owen). 



Idotea bicuspida OWEN, Crustacea of the Blossom, 1839, p. 92, pi. xxvn, fig. 6. 

 Idotea pulchra LOCKINGTON, Proc. Cal. Acad. Sci., VII, 1877, p. 44. 

 Edotea bicuspida MIERS, Jour. Linn. Soc. London, XVI, 1883, p. 66. 

 Synidotea bicuspida SARS, Crust. Norwegian North Atlantic Exp., 1885, p. 116, 



pi. x, figs. 24-26. BENEDICT, Proc. Acad. Nat. Sci. Phila., 1897, pp. 



391-392. RICHARDSON, Proc. U. S. Nat. Mus., XXI, 1899, p. 848; Ann. 



Mag. Nat. Hist. (7), IV, 1899, p. 268; American Naturalist, XXXIV, 1900, p. 



228. 



Localities. West coast of Alaska and Bering Sea; Kara Sea (Han- 

 sen). 



Depth. 3i to 81 fathoms, in mud, sand, and gravel; from sponges. 



Body ovate, about twice as long as wide, 12 mm. : 25 mm. Length of 

 abdomen equal to one-third the entire length of body, 8 mm.: 24 mm. 



Head with front produced on either side 

 of a median excavation in a wide border, 

 the lateral portion of which forms an an- 

 gle with the dorsal portion. Eyes large, 

 compound, and situated about the middle 

 of the head at the extreme lateral margin. 

 The first pair of antennae have the basal 

 article short and not dilated; the second 

 and fourth are about equal in length and 

 not longer than the first article; the third 

 is a little longer than any of the others. 

 The first pair of antennae extend to the mid- 

 dle of the thiri peduncular article of the 

 second pair of antennae. The basal article 

 of the second antennae is inconspicuous 

 from a dorsal view; the second article is 

 about as long as the first; the third and 

 fourth are each about twice as long as the second; the fifth is 

 nearly as long as the third and fourth together. The flagellum con- 

 sists of fifteen articles. The second antennae extend to the posterior 

 margin of the third thoracic segment. The maxillipeds have a palp of 

 three articles. 



The segments of the thorax are subequal along the median dorsal 

 line. The first is perhaps a little shorter. The epimera of all the 

 segments are coalesced with the segments, with no indication of a 

 2868905 25 



FIG. 424. SYNIDOTEA BICUSPIDA 

 (AFTER BENEDICT), x 2. 



