264 
SUPPLEMENT 
space left by the valves of the shell, which has been consi- 
dered as a matrix, and the function of which is to preserve the 
eggs after the laying, until the entire development of the 
young. The male organs are not known. The males, how- 
ever, are sufficiently distinguished by their large antennae, 
and generation appears to take place something after the 
manner of that of the batracian reptiles. 
The males of cypris are not known : all those which M. 
Straus submitted to the microscope were females. Their 
ovaries are very considerable, in the form of two thick, simple, 
conical vessels, terminating in a cul-de-sac, at their extremity, 
placed externally on the sides of the posterior part of the 
body, and opening one at the side of the other in the anterior 
part of the abdomen, where they communicate with the canal 
formed by the tail. In the present state of our knowledge, it 
is impossible to affirm whether these animals are hermaphro- 
dites, and necessitated to a reciprocal fecundation, or whether 
the males are only to be found at a certain period of the year. 
If, however, these animals be hermaphrodites, M. Straus is 
of opinion that we might consider in them, as male prepara- 
tory organs, two very short blind vessels, filled with a gelatin- 
ous substance, and which are situated above the mandibles; 
but, on the other hand, these same vessels might be taken for 
salivary glands, if they communicated with the oesophagus, as 
M. Straus suspects. 
Finally, in cyclops, the sexes are separate ; and we see at 
the time of laying, in the females, two vesicular sacs, or ex- 
ternal ovaries, situated at the base of the tail, and which are 
in all respects analogous to that which is found, but single, in 
the females of brancliipes. In the interior of the body, on 
each side of the intestinal canal, is an ovary, in the form of a 
vessel, similar to those of daphnis, and which communicates 
with the external ovaries. In the males, the second ring of 
