68 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



and narrow, with the extremity rounded. The peduncle of the uro- 

 poda is short and extends only half the length of the telson. The 

 inner lateral branch is placed at the extremity of the peduncle; it does 

 not quite reach the extremity of the telson, and is posteriorly rounded. 



FIG. 63. PTILANTHURA TENUIS. o, FIRST LEG. x 51|. b, FIRST ANTENNA, x 27}. c, SECOND 



ANTENNA. X 51|. d, MAXILLIPED. X 51|. , FIRST MAXILLA. X 51|. /, MANDIBLE (WITHOUT 



PALP), x 61|. 



The outer and superior branch extends to the end of the peduncle and 

 is somewhat triangular in shape, with apex acute. 



The first three pairs of legs are prehensile, the first pair being much 

 larger and stouter than the two following pairs. All the others are 

 ambulatory. 



IS. Genus ANTHELURA Norman and Stebbing. 



Segments of abdomen distinct in female. Flagella of both pairs of 

 antennas multi-articulate; that of first pair "in the male developed into 

 a remarkable brush-like organ nearly equal in length to half the animal, 

 and composed of very numerous, short, broad, and densely ciliated 

 joints." Maxillipeds with a palp composed of four articles. Mouth 

 parts otherwise as in Cyathura. 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS ANTHELURA. 



a. Uropoda with the outer and upper plates wide apart dorsally, broadly triangular 

 or spear-shaped, nearly as long as the inner plate, which is similar in form but 

 narrower. Telson broadly lanceolate, apex rather acute, about equal in length 

 to the uropods Anthelura abyssorum Norman and Stebbing 



a'. Uropoda with the outer and superior branches meeting dorsally, long, oval in 

 form. Inner branch with posterior margin widely rounded. Telson narrowly 

 linguiform, roundly triangular at the apex. Outer and superior branch as long 

 as telson. Inner branch extending beyond telson. .Anthelura affinis Richardson 



a See Norman and Stebbing for characters of genus. Trans. Zool. Soc., Lond., 

 XII, 1886, Pt. 4, p. 121. 



