DAPHNIOIDEA. J265 



G. 2. Daphnella, Baird* — Antennarum posticarum rami ambo 2-articulati, ramo 

 breviore interdum prope basin articulationem Stiam imperfectam habente. Caput 

 oblongum, infra non productum, antennas anticas medio gerens. 



G-. 3. Penilia, Dana.-f — Antennarum posticarum rami ambo 2-articulati. Caput 

 breve, infra acute elongato-productum, antennas anticas obsolescentes versus 

 apicem gerens. [Species marinse.] 



? G-. 4. Latona, Strauss.l — Antennae posticae ramis tribus 1-articulatis confectse. 



Fam. II. DAPHNIDiE.§ 



Pedes foliacei numero decern, latiores. Antennas anticse 1-2-articu- 

 latae. 



1. Tuhum cibarium medio non convolutum. Caput majusculum. 



G. 1. Daphnia, Mailer. — Corpus plus minusve oblongum. Antennae anticae mi- 



nutae, fere eelatae. Testa cellulis linearibus reticulata. 

 G. 2. Ceriodaphnia, Dana. — Corpus fere globosum, capite brevi. Antennae 



anticae minutae (raro elongatae ?) Testa cellulis hexagonis et pentagonis subtil- 



fssime areolata. 

 G. 3. Moina, Baird.\\ — Caput infra globosum. Antennas anticae longiusculae, 



apud capitis latus inferius pendentes. 

 Gr. 4. Macrothrix, Ba&rdl\ — Caput infra subacutum vel obtusiusculum, antennas 



anticas longiusculas pendentes ad rostri extremitatem gerens. Seta articuli lmi 



unius rami longa, alias superans. 



2. Tuhum cibarium medio convolutum. 

 a. Caput majusculum, ac in Daphniis. 

 Gr. 5. Acanthocercus, Schodler.** — Macrothrici similis. 



* Baird, Brit. Entomost., 109. 



f Proc. Amer. Acad. Sci., ii. 47. 



J The genus Latona is placed in this division by Schodler, on account of a general 

 resemblance to Sida, with a query as to its correctness. 



§ Dana, Proc. Amer. Acad. Sci., ii. 1849 ; Daphnita, Gray, Cat. Brit. Crust. Brit. 

 Mus., 88. Daphniadse (in part), of W. Baird, Brit. Entomost., 62. 



|| W. Baird, Brit. Entomost., 100 ; JPasithea, Koch, Deutschl. Crust. The name 

 Pasithea is rejected by Baird, because of its being previously used twice in Zoology. 



f W. Baird, Trans. Berw. Nat. Club, ii. 149, 1845, Ann. Mag. N. H., xi. 87, 1843, 

 xvii. 412, 1846, Brit, Entomost., 103. 



** E. Schodler, Archiv f. Naturgeschichte, 1846, p. 301. It is probable that this 

 genus should be united to Macrothrix. 



317 



