654 CRUSTACEA. 



ciliated with spinules, more than half shorter than outer caudal 

 lamella; this lamella spinulous on outer side, and much longer than 

 inner lamellae. 



Plate 43, fig. 6 a, animal, enlarged; b, caudal extremity; b', inner 

 caudaj lamellae; c, base of interior antennae; d, base of exterior an- 

 tennae ; e, one of the thoracic legs ; /, one of the scales of the ovarian 

 pouch ; g, h, i, h, I, m, young, in different successive states. 



Harbour of Rio de Janeiro. Collected in vast numbers, December, 



1838. 



Length, four to six lines. A cephalic portion of the carapax is partly 

 separated by a suture from the rest. Beak but slightly projecting. 

 Segments of abdomen nearly as long as broad, sixth nearly twice its 

 breadth in length. Outer caudal lamella quite long, one-third longer 

 than inner lamella, truncate at extremity, and rather stout spinulous; 

 inner lamellae nearly twice as long as caudal segment. Caudal seg- 

 ment of nearly equal width throughout. Eyes with a large pedicel, 

 stout and little oblong; facets very minute. Superior antennae with 

 second joint of base shortest, first longest. Upper flagellum about 

 two-thirds the length of the whole body, lower about half as long as 

 the upper. The upper is often thrown back, the two having the 

 position in the figure. The oblong scale at apex of base of these an- 

 tennae is stout, obtuse, and close ciliate. Inferior antennae full three- 

 fourths as long as body. The basal scale extends half its length or 

 more beyond apex of base, and gradually narrows to an obtuse point; 

 it is long ciliate on both sides. 



Eight pairs of thoracic legs of nearly equal length and similar 

 structure; the anterior pair a little the smallest, and increasing from 

 this to the seventh, eighth smaller than seventh. First joint of le- 

 compressed, broad triangular, second joint (or first of pediform branch) 

 very short, following three oblong, nearly equal, the last of the three 

 most slender and longest, all setose within in two ranges; at extre- 

 mity a distinct claw. Palpus much shorter than other branch ex- 

 tending a little beyond the apex of its penult joint, first joint nearly 

 round obovate, the rest of the organ slender and multiarticulate, con- 

 sisting of ten short joints. Plates of ovarian pouch in females concave 

 lunate, with the margin ciliate. The largest number of young seen 

 at any one time in this pouch was six, and they were in all states of 



