RRANCHIOPOUA. -"> / 



lacility on their hack, and their feet, which they cannot use for 

 walking, while thus employed, present a graceful and undulating 

 motion. This motion creates a current between them, which, follow- 

 ing the canal of the thorax, directs to its mouth the atoms which con- 

 stitute its food; when the animal wishes to advance it strikes the 

 water, right and left, with its tail, which forces it forwards by 

 hounds and leaps. Withdrawn from its element, it movr> its tail for 

 a while, and curves itself into a circle. Deprived of a certain degree 

 of humidity, it remains motionless. 



Benedict Prevost states, that when the male of the species which 

 constitutes the object of his memoir seeks his female, he swims 

 round her, seizes her by the neck with the two horn-like appendages 

 of his head, and remains fixed there, until she turns up the posterior 

 extremity of her tale, in order to approximate the two valves of the 

 copulating organs ; this process is analogous to the coitus of the Li 

 hellulie. The ova are yellowish, spherical at first, and afterwards 

 angular ; the shell is thick and hard, a circumstance which tends to 

 jiresi-rve them. It appears that even desiccation, provided it be not 

 carried to far, produces no change in the germ, and that the young 

 are hatched as soon as a sufficiency of rain has fallen. M. Desmarest 

 has frequently remarked Branchipi in the little hollows filled with 

 rain water, on the summit of the rocks at Fontainebleau. The female 

 Chirocephalus produces several distinct sets of eggs, after each copu- 

 lation, at different times, occupying some hours, and even the whole 

 day in the process. Each set consists of from one to four hundred 

 eggs ; they are rapidly ejected from the female in jets of ten or a 

 dozen, and with sufficient force to sink them slightly in the mud. 



Benedict Prevost has remarked that the Chir. diaphanus was sub- 

 jeet to certain diseases, of which he gives a description. This spe- 

 cies, as we have already stated, does not differ from our Branchipus 

 palustris *. The two horns, situated under the superior antennae, 

 are composed, in both sexes, of two joints, the last of which, how- 

 ever, is large and arcuated in the male, and very short and conical 

 in the female. In the Branc/tipn* xtagnalis^ the horns consist of a 

 single joint, and those of the males resemble the mandibles of the 

 Lin->inn< O/</M, in their form, dentations, and direction. 



Others have no tail; their body terminates almost directly behind 

 the thorax and last feet. Such is the 



EfTLIMENE, Lot. 



The body of the Eulimenes is almost linear, and has four nearly 



filiform antenna', two of which are smaller than the others, bearing 

 a great re.s.Miihlanee to palpi, and placed on the anterior extremity 

 of the head. Their head is transverse, with two eyes seated on large 



Cancer paludnsvs, MQ11. Zool. Dan. XI.YIII, 18; Herbst., XXXV, 35; 

 OMffNJpftlM diapkamuf Prcv., Journ. de Phys.; J,,rin., Mmi,.,-.. \\ \\ll 

 See Desroar., Consid. LVI, 35. This last species is described in the Manuel tlu 

 Naturalise of Duchesne, under the name of Martrau (Vrau douce. 



f Brtnchiopoda ttagnalis. Lat., Hist, des Crust, et des Ins., IV, p. 297 ; Cancer 

 staynalis, L. ; Gammanti stagnate, Fab. ; Apus pitc\farmif, Schcff. : Uammanu 

 H< \\V, 310. 



VOL. Ill 



