408 M. E. Hesse on the Pranizee and Ancei. 
The antenne are situated on the forehead, on each side of the 
rostrum. The nner antenne generally reach only to the third 
joint of the outer ones. They consist of four joints and a 
terminal filament of three jomts. The outer antenne present 
four joints, with a terminal filament of seven joints. The eyes 
appear like diffused spots on the sides of the head. The thorax 
is cylindrical, and composed of five segments, exclusive of that 
forming the neck. 
The digestive apparatus, which is very voluminous, is easily 
seen through the transparent skin; but the author could not 
trace the intestine to its inferior orifice; nor could he detect the 
circulation, except at the base of the abdomen upon the median 
lime. He distinctly perceived the movements of the blood- 
globules in the branchial false feet: these globules are subject 
to a regular impulse from right to left. . But im a female which, 
after the expulsion of her young, was as it were reduced almost 
to a mere skin, he was able to see that the globules of the blood 
are subjected to two opposite movements—namely, a median 
one towards the posterior extremity, and a lateral one directed 
forwards. 
The globules are of equal size, of an oval form, and rather 
wide apart; they are subjected to a regular jerking motion, 
comparable to the movement of the second-hand of a watch ; 
they are driven to the furthest extremities of the appendages, 
and here their motion appears to be more lively than at their 
centre. The impulsion of the heart is manifested throughout 
the median line, but is most sensible at the base of the thorax 
at its junction with the abdomen. 
The nervous or ganglionic system is readily visible in say= 
individuals, in consequence of their transparency. The thorax 
presents s7@ ganglia, of which the first is cephalic, and the last 
forms the base of the penis. The ganglia are lozenge-shaped, 
and united by a double interganglionic cord, of which, how- 
ever, the tubes are combined so as to leave no interval. Each 
ganglion emits on each side a very delicate nerve, which traverses 
the feet ; and the nerves of the fifth pair of feet emit a branch, 
which descends from the base of the feet to the first abdominal 
segment. 
The six ambulatory feet are composed of five joints, of which 
the first and last are the longest; the latter is terminated 
by a strong claw. In the youngest larvee the first pair, attached 
to the sides of the neck, do not present this construction. 
The abdomen likewise presents six joints, of which the first 
five are of equal size, and the sixth, which is usually larger, is 
of a triangular form. ach joimt has a double pair of branchiz 
or natatory feet: these are usually lamellar and ciliated, and at- 
