gg2 CRUSTACEA. 



dark-coloured mass, about half as long as the height of the head. The 

 upper antennae have the base rather stout and geniculated at the 

 second articulation ; the part of the base beyond is ciliate on the 

 lower side. The flagella of both pairs of antennae are long and very 

 slender. The abdomen consists of seven segments ; but the last three 

 are more or less soldered together, being marked in outline by sutures. 

 Of the three pairs of stylets, the first and third extend about equally 

 far backward, while the second pair falls short of this distance. The 

 six posterior legs are slender and subequal, and end in a slender claw; 

 the third and fourth pairs are equally slender and subequal ; the first 

 and second are much the smallest. 



These animals move with very quick motion, with head down, 

 turning over and over. 



Lestrigonus ferus. 



Thorax turnidus, segmentis anticis paulo indistinctis. Caput fronte 

 rotundatum. Antennae ferine corporis longitudine, Imce paulo Ire, 

 mores. Pedes 6 postici subcequi, coxd ad apicem rotundatd, ungue 

 dimidii tarsi longitudine. 



Thorax tumid, anterior segments indistinct. Head rounded in front 

 and hardly flattened. Antennae about as long as body, upper a 

 little the shorter. Six posterior feet subequal, coxa rounded at 

 apex, claw half as long as tarsus. 



Plate 67, fig. 6a, animal, enlarged; b, abdomen, side view; c, base 

 of superior antennae; d, exterior maxillipeds. 



Atlantic; latitude 2° north to 1° south, longitude 18° to 17° west. 

 Collected, 5 A.M., October 30, 1838; and also, November 3d and 5th. 



Length, one-eighth inch. Colour, brownish, or brownish red in 

 irregular spots, partly colourless ; basal joints of six posterior legs, 

 brownish red. Head about one-third of whole cephalothorax. Pig- 

 ment of eye, deep brownish red, nearly black. Third joint of base of 

 inferior antennae oblong, two preceding short. First pair of legs 

 smaller than second pair. Ciliae of natatory legs as long as the 

 lamellae to which they are attached. 



