818 CRUSTACEA. 



sextuple* longior quam lata, infra dente acuto pone medium et altero 

 ante medium armata, digito sat brevi. 



Body very slender, segments elongate, second thoracic segment nearly 

 twice as long as third, and very slender. Head hardly one-fourth 

 as long as next segment, bearing an acute spine on middle of dorsal 

 surface. Superior antennae longer than half the body; first joint 

 about half as long as second; flagellum eight to ten-jointed, 

 about half as long as base, the first joint very long and composite. 

 Inferior antennae about as long as first two joints of base of superior. 

 Branchiae nearly linear. Hand of second pair very narrow (about 

 one-sixth as broad as long), having an acute tooth just posterior to 

 middle of lower margin, and another anterior to middle. 



Plate 55, fig. 1 a, b, male, enlarged ; c, another variety ; d, flagel- 

 lum of superior antennae of same ; e, extremity of inferior, ibid. ; f 9 

 finger of anterior hands ; g, hand of second pair. 



Bio Janeiro, with the preceding ; abundant. 



Length, two-thirds of an inch. Colour, yellowish white, sometimes 

 with a tinge of red. The head is small, rather higher than long, and 

 but one-fourth as long as the first thoracic segment. The flagellum of 

 the superior antennae, is usually shorter than the two preceding joints, 

 and the first joint appears to be made up of ^Lve to seven segments, 

 indicated by the notches and setae of the margin. Inferior antennae 

 about as long as base of superior, excluding the last joint, which is a 

 long one. The last two joints together of the inferior antennae are 

 hardly as long as preceding joint. The anterior legs are about half 

 as long as basal joint of second pair. This basal joint is very slender, 

 and rather longer than the segment to which it is attached, and 

 longer than the hand of the same pair. The finger is hardly half as 

 long as hand. The second pair of feet is attached to second segment, 

 in the individual figured, very near its posterior margin. The palm 

 of the hand bears a few very short hairs. 



Var. subtenuis. — Our figure 1 c, represents this variety. It differs in 

 its less slender form, the second joint of the thorax about one-half 

 longer than the third, the inferior antennae slightly longer than the 



