570 NEW SPECIES OF rARASTTIC COPEPODS. 



armel with about five stout spines. The outer appendage is a long, 

 sltMitler si)ine or seta, arising from a minute fold of the skin. 



Male. — The males of this species are much smaller tlian the females, 

 being more slender and measuring only from two-fifths to one-half as 

 long. The cephalothovax is very large, composing very nearly one-half 

 the entire body in length, and is generally slightly wider than the 

 widest part of the thorax. It is subovate or subpvriform in outline, 

 from above, with the smallest end directed forward; thick, prou)inent, 

 and elevated above the plane of the thorax, from which it is well marked 

 oil". The front margin is rather broad, nearly straight or very slightly 

 convex, with the corners more or less abruptly rounded, back of which 

 the margins are slightly concave for a short distance; but the posterior 

 tliree-lburths in length of this segment form a very regular oval figure. 

 The thorax is narrowest directly back of the cephalothorax, but lYom 

 there it widens rapidly to near the middle, where the third pair of feet 

 originate, and where the width may neaily or quite ecpial that of the 

 first body segment. The feet of the third pair consist each of a simple, 

 narrow, elongate, gradually tapering appendage, terminating in an 

 acute or small rounded tip. They start from the lateral margins of the 

 thoraX; and are directed outwards and slightly backwards at a wide 

 angle with the sides of the thorax. Direcllj^ back of them the thorax 

 is again slightly and abruptly constricted, but immediately widens 

 again to give origin to the fourth pair of feet, the bases of which oc- 

 cupy the remainder of the thoracic margins. These appendages are 

 \ery elongate-lanceolate in shape, broaden gradually- from tlie base for 

 about one-third their length, and thence taper to acute or very small 

 rounded tips. Their total length is equal to the entire length of the 

 thorax and abdomen, plus one-third that of the cephalothorax, and they 

 are directed backward and slightly outward, as represented in Figs. 1 , 2, 

 Plate XXXIV. In fresh specimens, their greatest width is about one- 

 fifth their length, but iu alcohol, both the third and fourth pair of feet 

 become slightly narrower and thicker. Though of the same consistency 

 as the body, they have a somewhat stifl appearance, aiUl their propor- 

 tions and i)ositions are very constant in all the specimens examined. 



The abdomen is short, with convex sides. The caudal segment is 

 somewhat broader than long, abruptly constricted at the hinder end, 

 and terminates in two simple, elongate, tapering appendages, bluntly 

 rounded at the tips, and bearing three long, slender, acute papilhie 

 each, one of which is at the tip and two in front of the middle. 



The appendages in advance of the third pair of feet are all propor- 

 tionally large, and when compared with the corresponding appendages 

 of tlie females are seen to resemble them closely in shape and structure. 

 As they are all figured on Plates XXXIV and XXXV, detailed descrip- 

 tions of them will not be given. The anterior anteinne project consid- 

 erably at the sides of the head, and consist of at least six segments, 

 with )iumerous elongate terminal papilhe and a few distributed else- 



