TANAIS. Eat | 
joint armed with strong sete; these two divisions are 
fixed upon an oblong movable basal joint. The outer 
pair of maxille, according to Savigny, consists of a 
pair of organs, each of which is formed of three slender 
oval plates lying upon each other and arising from an 
oblong basal joint. 
The pair of foot-jaws (g), closing the mouth from 
beneath, is of large size, brought into contact with each 
other along the inner edge of the basal half, the first 
joint being nearly square, but with the base produced at 
the inner angle; the second joint is short, but swollen on 
the outer edge and produced within into a flat oval plate, 
ciliated along the margin; the third and fourth joints 
respectively are nearly triangular in form, with a strong 
pencil of hairs on the inner margin; and the terminal 
joint is slender, curved, and affixed at the apex of the 
preceding joint so as to rest upon its inner edge, the 
top and inner margin being also furnished with a long 
pencil of hairs. The organs of the mouth occupy nearly 
the whole of the under-side of the conjoined head and 
first segment of the body, leaving the laterally-dilated 
posterior angles for the insertion, on the under-side, 
of the base of the large first pair of legs. 
The first pair of legs are not only evidently very 
powerful organs of prehension, but are also employed 
by the animal for the defence of the parts of the mouth, 
upon which, when unemployed, they fold very closely. 
They are of large size and very robust, with the wrist 
oblong, and the hand large and sub-ovate, set on the wrist 
obliquely, having the infero-anterior angle produced into 
a strong fixed finger, against which the movable apical 
finger works, forming a powerful didactyle claw. The 
second pair of legs are more slender than the remainder, 
and somewhat longer than the third pair; the segment of 
