184 Bulletin Vanderhilt Marine Museum, Vol. V 



The ambulatories are well developed ; the third pair of legs are the 

 longest of the series, while the third and fourth pairs are about equal 

 in length, the first pair of legs being the shortest. All four pairs have 

 the merus widened ; the merus of the first pair of legs is not conspicu- 

 ously widened, being one-fifth narrower than those of the other pairs ; 

 the merus of each the second, third and fourth pairs of ambulatories 

 has a width equal to about one-third of its length ; the anterior lateral 

 margin of each merus is set with a series of about nine acute, outward 

 and forward directed spines which slightly diminish in size toward 

 the proximal end of the series, the distal one being at the tip of the 

 joint; the posterior margin of the merus is carinate, the carina ter- 

 minating in a subdistal spine ; a fine short fringe of setae arises from 

 the anterior side of the carina and extends upon the dorsal surface of 

 the merus ; a secondary line of spinules approximately parallels those 

 of the anterior margin, increasing in size from proximal to distal and 

 terminating in an acute subdistal tooth. There are two distinct longi- 

 tudinal flat carinae separated by a wide shallow sulcus, on the dorsal 

 surface of the merus. The anterior carina bears the row of secondary 

 spinules ; on the other carina there are a few flat granules. The carpus 

 is one-half as long as the merus and only about half as wide, with both 

 upper margins carinate and fringed with short setae and with a sub- 

 distal spine on the posterior margin ; the propodus is two-thirds as long 

 as the merus, narrow, slightlj^ tapered, with a conspicuous longitudi- 

 nal fringe of setae on the upper surface and less conspicuous fringes 

 each on the carinate anterior and posterior lateral margins and other 

 tufts of long setae set between these; the dactyl is strong, scarcely 

 one-half the length of the propodus, curved and with a strong, claw- 

 like tip ; besides this there are a series of four or five sharp, obliquely 

 set spines along the inferior lateral margin. 



References : Acanthopus pilimanus A. Milne Edwards, Nouv. Ar- 



chiv. Mus. Hist. Nat. t. IX, p. 300, pi. 14, fig. 5, 1873. 

 fLeilophus pilimanus Miers, Ann. Mag. Nat. Hist. ser. 5, vol. I, p. 154, 



1878. 

 ^Acanthopus affinis A. Milne Edwards, Ann. Sci. Nat., ser. 3, Zool. 



XX, p. 180, 1853. 

 ^Acanthopus tenuifrons A. Milne Edwards, ibid., vol. XX, p. 180, 



1853. 

 Percnon pilimanus M. J. Rathbun, Bull. U. S. Fish Comm., vol. 23, 



pt. 3, p. 842, for 1903, issued 1906. 



