BBANCHIOPODA. 255 



ova of the females are contained in an elongated capsule, situated 

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

 in the posterior extremity of the body and thorax in those wliich 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. Fab.; Desmar., 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. Prevosl, 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 

 terminated by two leaflets more or less elongated and edged with 

 cilia. 



Although Schseffer and Benedict Prevost*, have published very 

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

 imperfect with respect to the profound and comparative study of the 

 organs of the mouth, and of some other parts of the head. Considering 

 the two sexes together, we find the following general conformation : 

 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 compressed feet, 

 usually composed of three foliaceous joints, with a fringe of hairs or 

 bearded threads along the edges ; and of an elongated tail tapering to 

 a point, consisting of nine segments terminated by two more or 

 less elongated leaflets fringed with cilia. Under its second segment 

 we find the male organ of generation, and in the female an elongated 

 sac containing the ova she is ready to produce. In the head we 

 observe, 1. Two reticulated eyes situated at the extremity of two 

 flexible peduncles formed by lateral prolongations of the head ; 

 2. Two antennae at least, frontal, scarcely longer than the head, 

 slender, filiform, and composed of very small joints ; 3. Two projec- 

 tions under them, sometimes resembling a uniarticulated horn, and 

 at others digitiform — the premier doigt des mains, Uened. Prevost — 

 and biarticulated ; 4. A mouth underneath, composed of two kinds 

 of dentated mandibles without palpi, and of some other parts. We 

 suspect that these horn-like projections are merely an appendage, 

 larger and differently formed in the males, of the frontal antennae ; 



* M(^m. sur le Chirocephale printed at the end of the Hist, des Monoc. of tlie 

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



