HRANCHIOl'ODA. 
253 
carried along by the ciiirerit formed by tlie action of tlieir feet, which 
directs their ordinary aliment towards their mouth. They use the hooks 
which terminate the extremity of their tail to clean their hranchia?. 
Daphnia pulex ; Monoculux pulex, L. ; Pulex aqualicus arho- 
rescens, Swamm., Bib. Nat., xxxi ; Perroquel d'eau, Geoff., 
Hist. Ins. II, 455; Schsef., Die Griin., arm.. Polyp., 1755, I, 1,8; 
Straus, Mem. du Mus. d’Hist. Nat. V, xxix, 1 — 20; Jurine, 
Mon., viii — xi. According to Straus, this species has a large 
convex rostrum; setae of tlie oars plumose; first tubercle of the 
sixth segment linguiform ; inferior edge of the valves dentated ; 
valves terminated by a short tail, which is obtuse in the females. 
This last character distinguishes it from another species with 
which it has been confounded, the 
Dapli. lonfjispina, Str. Deg. Insect. VII, xxvii, 1 — 4. The 
female is four millimetres in length ♦. 
I’he last suhgenus of the Lophyropa is 
Lynceus, Miill . — Chilodorus, Leach. 
It can scarcely he distinguished from the preceding except by the 
oars, evidently shorter than the shell, the inferior portion of which 
has hut little or no projection. According to Straus the articula- 
tions of the branchiae are more numerous than in the preceding sub- 
genera. They all have a little spot before their eye which has the 
appearance of a second one. The rostrum, longer in proportion than 
that of the Daphniae, is curved and j)ointed f. 
The second section of the Branchiopoda, that of the Phyllopa, is 
distinguished from the first, as already stated, by the number of feet, 
which at least amounts to twenty J and by the lamellated or foliaceous 
form of their joints. There are always two eyes, which are some- 
times pediculated : several of them have also an ocellus. 
They form two principal groups. 
In the first — Ceratopthalma, Lat. — there arc never less than ten 
pairs of feet, nor more than twenty-two ; the vesicular body at their 
base is wanting; the anterior are never much longer than the others, 
nor ramified. The body is contained in a shell resembling that of a 
bivalve, or is naked, each thoracic segment bearing a pair of exposed 
feet. The eyes are[sometimes sessile, small, and closely approximated ; 
at others, and most frequently, they are situated at the extremity of 
two moveable pedicles. The ova are internal or external, and are 
contained in a sac at the base of the tail. 
Here the eyes are sessile and immoveable ; the body is invested 
* For the other species, see Mem. cit. of Straus; Miill., Entom., and Jurine, 
Hist, des Mon. fain. II, p. 185 — 8S, and p. 181, 200. For the ii. sima and />. 
loiujisjiina, see Itaud., Monoc., V-VIl. 
•f See Miill., iMitoin., G. lynceus-, Jurine, Monoc. p. 1.5l, 158; and Desmar., 
Consul., 375 — 378. 
J These animals represent among the Crustacea, the Myriapoda of the class of 
Insects. 
