1140 



CRUSTACEA. 



south, longitude 124° 30' west; also (fig. 3), November 6, 1838, lati- 

 tude 2° south, longitude 20° west. 



Length, one-eighteenth of an inch. Colour (fig. 2 a), deep blue, with 

 pearly white reflections along the back; also (fig. 3), blue with red, 

 and a yellowish band occupying the larger medial part of the cephalo- 

 thorax. 



The cephalothorax of iig. 2 a is rather broadest posterior to the 

 middle. Furcation of beak long and flexed inward. Last thoracic 

 segment very short and much narrower than the preceding. Abdomen, 

 excluding stylets, not one-fourth the cephalothorax in length. Caudal 

 stylets more than half as long as abdomen. Caudal setae four, sub- 

 equal, with a minute spine exterior to the four, and another within. 

 The basal joint of the anterior antennae is directed more directly 

 forward than the following part of the organs. Near the middle, or 

 about seven joints from the apex, the antenna is abruptly smaller than 

 the part below. The posterior subapical setae are shorter than the 

 anterior penult, and the latter is less than the length of penult joint. 

 The four pairs of natatories are nearly equal, the posterior a little 

 the smallest ; the fifth pair is very minute. 



The specimen figured in fig. 3, differs from the preceding in not 

 having the back pearly white. Moreover the antennae are shorter, 

 being about three-fourths as long as the cephalothorax, and containing 

 only about fourteen joints. It agrees with the preceding in form, in 

 the position of the antennae, the terminal setae, the short two-jointed 

 abdomen (less than one-fourth the cephalothorax), minute points to 

 the posterior extremity of the thorax, and in having the setae of the 

 longer branch of the posterior antennae so long as to extend to the 

 penult segment of the thorax (counting only three, instead of four pos- 

 terior segments) . The pigment of the inferior eyes is also large. The 

 shorter branch of the posterior antennae is about half as long as the 

 other. Length, one-twelfth of an inch. It may be distinct. 



Plate 80, fig. 4 a, 6, represents another species, unless it may be 

 young of the last. It was collected on the same day, November 6, 

 1838. I have it named in my manuscript Pontia ciirticomis. The 

 body is slender ; head separate and rounded in front. There are three 

 posterior thoracic segments, of which the last is quite short, narrow and 

 obtuse behind, and appearing as if it belonged to the abdomen. The 

 abdomen is two-jointed, the second segment longest; whole length not 



