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 microscoj^e 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 cesophagus, 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 branchipes. 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 daphuis, and which communicates 

 with the external ovaries. In the males, the second ring of 



