134 CRUSTACEA. 



the same time as the females, which is during the month of June, 

 and are unknown. 



Limnadia Herman^ Ad. Brongn., Mem. du Mus. d'Hist. Nat., 

 VI, xiii; Daphnia-gigas, Herm., Mem. Apterol., V. Found in 

 great numbers in the little pools of the forest of Fontainebleau. 

 There, each eye is situated at the extremity of a pedicle, formed 

 by a lateral prolongation, in the shape of a horn, of each side of the 

 head. The body is naked, without a shell, and annulated throughout. 

 The ova of the females are contained in an elongated capsule, situ- 

 ated near the base of the tail in those which are thus terminated, or 

 in the posterior extremity of the body and thorax in those which 

 have no tail. 



Some are provided with a tail. 



Artemia, Leach. 



Eyes placed on very short pedicles; the head confounded with an 

 oval thorax, furnished with ten pairs of feet, and terminated by a 

 long and pointed tail. The antennae short and subulate. 



A. salina; Cancer salinus, L. ; Montag., Trans. Lin. Soc. XI, 

 xiv, 8 — 10; Gammarus salinus, Yah.; Desmdir., Consid., p. 393. 

 A small species found in the salt marshes of Lymington, in 

 England, when nearly dry, of which as yet we have but a very 

 imperfect account. 



Branchipus, Lat. — Chirocephalus, B. Prevost, and Jurine. 



Eyes placed on projecting pedicles; the body narrow, elongated 

 and compressed; the head distinct from the trunk, furnished with 

 appendages varying according to the sex, and with two appendages 

 resembling horns between the eyes; eleven pair of feet; the tail termi- 

 nated by two leaflets more or less elongated and edged with cilia. 



Although Schoeffer and Benedict Prevost(l) have published very 

 detailed monographs of two species of this genus, they are still 

 imperfect with respect to the profound and comparative st^dy of 

 the organs of the mouth and of some other parts of the head. Con- 

 sidering the two sexes together, we find the following general con- 

 formation; the body is almost filiform, composed of a head separated 

 from the trunk by a kind of neck; of a trunk or thorax longitudinally 

 hollow beneath, divided, at least above, exclusive of the neck, into 

 eleven segments, each bearing a pair of branchial, strongly com- 

 pressed feet, usually composed of three foliaceous joints, with a 



(1) Mem. sur le Chirocephale printed at the end of the Hist, des Monoc. of the 

 late Lewis Jurine, and previously published in the Journal de Physique. 



