118 
BRITISH ENTOMOSTRACA. 
communication with it, and is immoveable. It is not 
composed of crystallines, and its situation is not exactly 
the same in all the species. 
Jurine says he has only examined it in small indi- 
viduals, and that in consequence he has not been able to 
discover its utility. He does not appear to have met 
with the larger individuals of this family, such as the 
Eurycercus lamellatus , in which I have examined this 
spot, but without being able to ascertain any use to 
which it is applied. I quite agree with him, however, in 
considering it to be not an organ of vision. 
Straus considers the upper larger spot the only one 
deserving the name of eye, and this small black spot 
to be similar to that existing in the Daphniadae ad- 
jacent to the brain, the relative situation of which is 
also nearly the same as this black spot in the Lynceidae. 
We find it in the young before birth exactly as in the 
adult. 
The antennae are four in number, two superior and two 
inferior, and are situate as in the Daphniadae. The su- 
perior antennae (t. XV, f. 1 a) consist each of a solid body, 
of a somewhat conical shape, and slightly curved, which 
terminates in six short spines, each of which again gives 
out a fine seta or bristle. They are not possessed of much 
motion. The inferior antennae, or rami as they are some- 
times called (t. XV, f. 1 b), are situate on each side of the 
base of the head, rather lower than in the Daphniadae, 
and consist, as in them, of a single joint at the base, which 
divides into two branches, each having three joints ; they 
are much shorter in all the species than in the Daphniadae. 
In the Eurycercus lamellatus the anterior branch sends off 
from the last joint three long filaments or bristles, and a 
short one, and one from the extremity of the second and 
first joints ; while the posterior branch sends off only 
three long ones and a short one from the last joint. The 
long setae are each furnished with a joint near the centre, 
as in Daphnia pulex , and, as in it, are beautifully plumose, 
while the short setae are neither jointed nor plumose. 
