1250 



CRUSTACEA. 



Finger of posterior antennae rather slender, very nearly as long as the 

 second joint, the claw hardly half the length of the finger. Caudal 

 lamellae distinctly shorter than twice their length, ovate, having a 

 tooth on inner side near apex, setae four, scarcely half as long as 

 the lamellae, two apical the others external. Male: — Body flat, 

 subovate, ten-jointed, first segment the broadest and somewhat 

 transverse, last nine segments gradually decrease in breadth, the 

 tenth is concealed beneath the ninth. Conspicilla on the front. 

 Female: — Body convex. Cephalothorax oval, five-jointed, first seg- 

 ment hardly longer than the breadth, posterior having the sides 

 nearly rectangular, and at middle behind a little prominent. Con- 

 spicilla of moderate size, in contact, on the front. Abdomen six- 

 jointed, oblong, first segment quite small, sides truncate, second 

 with sides rounded, third, fourth and fifth lunate, acute. 



Plate 87, fig. 13 a, female, enlarged; 6, part of posterior antenna; c, 

 caudal lamella. Fig. 14 a, male, enlarged ; a', posterior antenna; b, 

 anterior antenna ; c, under view of anterior part of animal. 



East Indies, Sooloo Sea, southwest of the island of Panay, January 

 29, 1842. 



Length, one-tenth of an inch. Colour of female, deep blue black. 

 Colour of male, bright opal tints ; imperfectly transparent. 



It is not certain that the male and female here described are of the 

 same species. The only evidence of this consists in their having been 

 collected on the same day, and their having similar anterior and posterior 

 antennae, conspicilla, and caudal lamellae. 



The body of the male is broadest at the first articulation, and from 

 thence the sides are straight convergent. The length is twice the 

 greatest width, or nearly so. The segments are laterally obtuse, 

 excepting the two or three last, which are acute or nearly so. The 

 length of the caudal lamellae is one and two-thirds the breadth, which 

 is a little shorter in proportion than in the female. 



