ISOPODS OF NORTH AMERICA. 



171 



five articles. The frontal lamina has the large round disk of the base 

 ventrally placed, not anteriorly directed. 



The first segment of the thorax is a little longer than any of the 

 others, and the seventh is shorter. The epimera of all the segments, 

 from the second to the seventh, inclusive, are distinctly separated from 

 the segment. They are narrow, with the posterior angle in the last 

 four acutely produced beyond the posterior margin of the segments. 

 The first two epimera are rounded posteriorly. A distinct carina 

 extends obliquely from the posterior angle to the inner antero-lateral 

 angle in all the epimera. 



The six abdominal segments are all distinct. The lateral parts are 

 not separated off from the dorsal portion. The sixth or terminal seg- 

 ment is triangularly produced in a long and very acute point, extending 

 2 mm. beyond the extremity of the 

 uropoda. The branches of the uro- 

 poda are equal in length. The inner 

 branch has a conspicuous notch or 

 emargination on the exterior margin 

 about 2 mm. from the posterior ex- 

 tremity which is acutely produced. 

 The outer branch is about as wide as 

 the inner branch, the margins are 

 entire, and the posterior extremity 

 rounded. The branches of the uro- 

 poda are crenulate and furnished with 

 spines. The basal article or peduncle 

 extends half the length of the last 

 segment of the abdomen. 



The first three pairs of legs are prehensile, the last four pairs ambu- 

 latory. There are five spines on the merus of the second and third 

 pairs of legs. The last four pairs of legs are thickly beset with spines. 



JEGA ECARINATA Richardson. 



-ffiga ecarinata RICHARDSON, Proc. Biol. Soc. Washington, XII, 1898, pp. 39-40; 

 American Naturalist, XXXIV, 1900, p. 218; Proc. U. S. Nat. Mus., XXIII, 

 1901, p. 521. MOORE, Bull. U. S. Fish Comm., XX, Pt. 2, 1902, p. 171, 

 pi. x, fig. 1. 



Localities. Off Little Bahama Bank, between delta of the Missis- 

 sippi and Cedar Keys, Florida; off entrance to San Juan. 



Depth. 88-338 fathoms. 



Body elongate and narrow. Length more than three times greater 

 than breadth. Surface punctate. Frontal margin of head bisinu- 

 ated, the acumen separating the first pair of antennae. Eyes large and 

 oblong and situated a small distance apart. First pair of antennas 



FIG. 150. JEGA ANTILLENSIS. a, MAXILLI- 

 PED. x 27}. 6, LEG OF SECOND PAIR, x 9|. 



