1154 CRUSTACEA. 



Length, one-tenth to one-fifteenth of an inch. Colour, deep blue. 

 This is rather a stout species, with a triangular head laterally armed 

 and very short points (if any) at the posterior extremity of the 

 cephalothorax, the fourth of the posterior segments being extremely 

 short. The joints of the antenna? are all very short except the 

 second; the setae are all remarkably short, and those at apex are 

 straight. The abdomen sometimes shows in addition to the three 

 segments mentioned, a short basal segment ; the length of the whole 

 is scarcely one-fourth that of the cephalothorax. The stylets are 

 longer than half the abdomen, and a little divergent. 



The superior eyes have a deep carmine pigment. The pigment of 

 the inferior eyes, as seen in a vertical view, forms a rather large spot, 

 a little oblong transversely, and is seen just behind the superior eyes. 

 The segments of the abdomen are variable. 



The .right antenna (fig. 9 c?), in a specimen collected February 5, 

 1841, differed from the left; but as the posterior feet were quite small, 

 there was no reason to consider the specimen a male. It had the 

 same number of joints as the left, but was slightly enlarged along the 

 middle. 



Figure 3, Plate 82, represents a specimen obtained in the Pacific, 

 north of the Samoan Islands, February 1, 1841, which is probably a 

 variety of the detonsa. The anterior antennas diverged about 115°; 

 the setae were all short, the apical and subapical very nearly equal, the 

 anterior apical barely exceeding the joint in length. 



The Pontia Savignii of Edwards (Ann. des Sci. Nat., xiii. 1828, 

 296, PI. 14), has the short antennaa and some other characters of the 

 female of P. detonsa. But the hairs of the anterior antennas as repre- 

 sented differ, being much longer, those of the joints about the middle 

 of the organ being twice as long as the joints, and these joints more 

 than twice as long as broad ; moreover, the apical and subapical setae 

 are very different; and the maxillae are also of different form. 



PONTELLA ARGENTEA. 



Caput discretum, subtriangulatum, /route obtusum. Cephalothorax 

 5 (-§)-articidatus, postice brevissimd acutus, segmentis tribus posticis sub- 

 ozquis. Oculi superiores remoti, inferiores rnajusculi non elongati. 



