ISOPODS OF NORTH AMERICA. 79 



abrupt!} 7 narrower than the sixth, not as wide as the abdominal seg- 

 ments and devoid of legs. 



The first three pairs of legs are subchelate, the three following 

 pairs ambulatory. 



The abdominal segments are well defined and distinct from one 

 another. The terminal abdominal segment is rounded, entire. The 

 inner branch of the uropoda is likewise rounded; the outer and supe- 

 rior branch arches over the telson. 



This genus agrees with both Hyssura Norman and Stebbing and 

 Cruregans Chilton in the absence of the seventh pair of legs, but dif- 

 fers from the first named in the structure of the antennae, both pairs 

 of antennae in Hyssura having multi-articulate flagella; in the structure 

 of the outer branch of the uropoda, which in Hyssura does not arch 

 over the telson; and in the structure of the mouth parts. Colanthura 

 differs from Cruregans in the presence of eyes, which are wanting in 

 Cruregans^ and in the structure of the outer branch of the uropoda, 

 the outer branch in Cruregans being very narrow and not arching 

 over the squamiform telson, while in Colanthura the outer branch is 

 broad and arches over the rounded terminal segment. The structure 

 of the mouth parts is the same as found in the genera Paranthura, 

 Calathura, and Cruregans. 



COLANTHURA TENUIS Richardson. 



Colanthura tenuis RICHARDSON, Trans. Conn. Acad. Sciences, XI, 1902, pp. 287- 

 288, pi. xxxvm, figs. 23-28. 



Locality. Bermudas. 



Body narrow, elongate; surface smooth; color light yellow. Head 

 with a prominent median process extending between the first pair of 

 antennae. Antero -lateral angles prominent, produced, reaching the 

 distal end of the first joint of the peduncle of the first pair of antennae. 

 Eyes large, conspicuous. 



First pair of antennae consist of four joints, the terminal or flagel- 

 lar joint being fringed with long hairs. The second pair of antennae 

 are composed of five joints, the terminal joint being fringed with 

 hairs. 



The first three thoracic segments are about equal in length. The 

 fourth and fifth segments are each much longer than any of the three 

 preceding segments, and are about alike in size. The sixth segment 

 is short, not quite as long as any one of the first three segments. 

 The seventh is ver} r short, being one -third the length of the sixth 

 segment, and in both specimens examined is devoid of legs. 



The segments of the abdomen are distinct, the first five together not 

 being as long as the sixth thoracic segment. The last thoracic seg- 



