150 TANAIDE. 
also composed of a considerable number of articuli. The 
lower antennz are much shorter than the upper, the 
basal joints being the thickest, the third furnished with a 
small oval squamose plate at its extremity, the terminal 
joints or flagellum slender, extending beyond the base 
of the flagellum of the upper. The upper surface of 
the head is uneven (the fissures probably marking the 
point of fusion of the head with the first joint of the 
body), terminating in front in a porrected point. The 
eyes are aflixed upon a pair of short, somewhat kidney- 
shaped lobes. The outer foot-jaws are short, and ciliated 
on the inner margin. The mandibles are elongated, 
gradually narrowing to the tip, which is denticulated ; 
they bear a slender, three-jointed appendage, the first 
joint of which is very short, the second and third longer 
and nearly equal in length, the latter furnished with long 
bristles at the tip, set on at right-angles to the joint. 
The first pair of legs are robust, the wrist is swollen, 
and armed on its under side with two tubercles a short 
distance apart; the hand is large and oval, its inferior 
angle produced into a finger, having a tubercle on its 
inner edge near the middle, against which the true finger 
impinges, the latter having a small tubercle on its inner 
edge, close to its base. The second pair of legs have the 
hand developed into a large, transversely flattened ovate 
joint, having several strong spines on its margins, so as 
to give it a digitated appearance, the terminal finger 
resembling one of these spines. The third and fourth 
pairs of legs are slender, having a forward direction, the 
penultimate joint is very slender, except at the tip, which 
is dilated and fringed with spinous hairs, the slender 
terminal finger inserted on its posterior surface within 
the tip. 
The fifth pair of legs are also slender, but with a back- 
