ENTOMOLOGICAL SOCIETY OF FRANCE. * 133 



M. AuDOUiN submitted to the Society some Crustacea which 

 he had received from M. Bravais, and which were very remark- 

 able on account of their similarity to certain bivalve shells ; 

 many Crustacea possessing this character, as CytJiere, Cypris^ 

 Ly7iceus, and Lhmiadia, were already known, but here the 

 resemblance was much more complete, for the cross stria3 of 

 the shell were readily to be traced, and its size was at least a 

 centimeter; nevertheless, the class to which these animals 

 belonged could not be mistaken. These Crustacea, M. Au- 

 douin considered, ought to constitute a new genus, allied to 

 Lynceus, and would connect this genus with LimnacUa: they 

 will form the subject of a future paper. They were found in 

 a little pond of brackish water at Arzen, near Oran, on the 

 coast of Africa; in the same pond Dytisci were captured. 



M. AuDOTJiN then exhibited to the Society some Crustacea, 

 very nearly related to the above, which he had received from 

 M. Deshayes. These Crustacea, which equal in size those of 

 Arzea, have been found in different provinces of the Russian 

 Empire ; and a naturalist of that country, M. Krynecki, has 

 recently published a description of them in the " Bulletin de 

 la Societe cles Naturalistes de Moscou," under the name of 

 Limnadia tetracera. M, Aiylouin entered minutely into the 

 structure of these Crustacea, and clearly demonstrated that 

 they could not be placed in the genus Limnadia, that they 

 approached much more nearly to Lynceus, and indeed that they 

 belonged to the same genus as the Crustacea previously ex- 

 hibited from Arzen: to this new genus he proposed the name 

 Cyzicus, a genus composed at present of but two species, 

 C. Bravaisii and C. tetracerus. M. A.udouin then remarked 

 on the widely separated habitats of the two species, Russia 

 and the Coast of Africa ; and observed that it was by no means 

 a solitary instance of genera, at present composed of very few 

 species, being found dispersed over far distant regions of the 

 globe ; even confining himself to the Eutomostraca, he would 

 cite the genus Limnadia, which, till lately composed of a 

 single species, a native of France, was now enriched by a 

 second, very similar to the first, which had been found by 

 M. Desgardin in the Island of Maurice, situated within the 

 tropics. Reverting to the Entomostraca of Arzen and of 

 Russia, M. Audouin observed that he had found among them 

 both males and females ; this fact he considered of great 



