GAMMARIDEA. 337 



Length, four lines. The eyes are subrotund. The first thoracic 

 segment is a little longer than the following. 



The base of the superior antennae is but half as long as base of 

 inferior and consists of three subequal joints; the flagellum con- 

 tains ten to twelve joints, with a few extremely short hairs at the 

 apex of each joint. The flagellum of the inferior antennas has the 

 joints a little the smallest at base. 



The hand of the first pair of legs is sublinear, a little longer than 

 twice the breadth. The short claw shuts against the oblique terminal 

 edge. There are a few short setae on the inferior surface of the hand. 

 The finger of the second pair is longer than half the length of the 

 hand. 



The sixth and seventh pairs of legs are about equal. The maxil- 

 lipeds have the last joint narrow and the terminal spine small. The 

 abdominal natatory legs are long and slender. 



Allorchestes verticillata, Dana, Proc. Anier. Acad. Sci., Boston, ii. 205. 



Female of A. verticillata? — Figures 3 a to h, Plate 60, illustrate a 

 species of Allorchestes, which we suspect to be the female of the A. 

 verticillata. Still, it is different in some points that appear to be im- 

 portant. The short hairs or setae of the flagellum of the inferior 

 antennae are not as dense and hardly as long ; the setae of the legs 

 are stout, as in the verticillata, but shorter; on the fifth joint of the 

 last pair, there are four sets of setae on the under side, none more than 

 half the diameter of the joint in length, excepting the lower, which 

 is but slightly longer. The proportion between the pairs of antennae 

 is about the same. 



The hand of the first pair of legs is similar in form and size to that 

 of the verticillata. The hand of the second pair is a little larger than 

 that of the first pair, not twice as long or as broad, and has some 

 resemblance in form to the first pair ; it is oblong, rather broad, the 

 upper and under sides nearly parallel, the upper very slightly arcuate, 

 and one-third the longer, the lower with three or four tufts of longish 

 setae, the apex truncate a little obliquely, forming a nearly transverse 

 palm and somewhat hairy, the finger not longer than the margin 

 against which it is applied, and not half as long as the hand ; the 

 carpus is broader than the third joint; the third joint is nearly 

 rectangular. The flagellum of the superior antennae is ten to twelve- 



