132 CRUSTACEA. 



cens, Swamm., Bib. Nat., xxxi; Perroquet 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 the 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 



Daph. longispina, Str. Deg. Insect. VII, xxvii, I 4. The 

 female is four millimetres in length(l). 

 The last subgenus of the Lophyropa is 



Lynceus, Mull. Chilodorus, Leach. 



It can scarcely be distinguished from the preceding except by the 

 oars, evidently shorter than the shell, the inferior portion of which 

 has but little or no projection. According to Straus the articula- 

 tions of the branchiae are more numerous than in the preceding 

 subgenera. 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 pointed(2). 



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(3) and by the lamellated or 

 foliaceous form of their joints. There are always two eyes, which 

 are sometimes pediculated: several of them have also an ocellus. 



They form two principal groups. 



In the first Cehatopthalma, Lat. there are 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 ex- 

 posed feet. The eyes arc sometimes sessile, small and closely ap- 

 proximated; at others, and most frequently, they are situated at the 

 extremity of two movable pedicles. The ova are internal or external, 

 and are contained in a sac at the base of the tail. 



(1) For the other species, see Mem. cit. of Straus; Mull., Entom., and Jurine, 

 Hist, des Mon. fam. II, p. 185 58, and p. 181, 200. For the D. sima, and D. 

 longispinu, see Rand., Monc. V VII. 



(2) See Mull., Entom., G. lynceus; Jurine, Monoc. p. 151, 158; and Desmar., 

 Consid., 375378. 



(3) These animals represent among the Crustacea, the Myriapoda of the class 

 of Insects. 



