412 Dr. Bairil on some new Genera and Species 



Berw. Nat. Club ' for 1845, I have proposed forming a distinct 

 family for receiving all those species of the genera Daphnia and 

 Lyncetts of Miiller that have the antennules pendulous from the 

 beak. In the 'Ann. Mag. Nat. Hist.' xi.p.87, 1 have arranged the 

 genus Macrothrix, provisionally, under the fam. Lq/nceidcEj as it 

 possesses only three articulations to each joint of the large an- 

 tennse, and has also the black point in front of the eye. I have 

 now ascertained however that it has not the articulated abdomen 

 nor the convoluted intestine that form such distinguishing marks 

 in the Lynceidce, being in these respects formed like the Daphnidce. 

 It cannot thus be received into that family, and as in its position 

 of antennules it agrees with the D. cornuta, I now propose ar- 

 ranging it in the same family. The two families and genera will 

 be thus characterized : — 



Fam. I. DAPHNID^. 



Two pairs of antennae ; superior very small and situated under 

 the beak, inferior large, two-branched, and used as organs of lo- 

 comotion. Five pairs of feet. Head prolonged into a more or 

 less obtuse beak. Eye single, large. Intestine straight. 



This family contains two British genera, Daphnia and Bida. 

 (Trans. Berw. Nat. Club, 1845, p. 148.) 



Fam. n. BOSMINID^. 



Two pairs of antennse j superior longer than in preceding fa- 

 mily, and pendulous from or articulated to the extremity of the 

 beak. In other respects as in Daphnidce. 



This family contains two British genera, Bosmina and Ma- 

 crothrix. 



Gen. 1. Macrothrix, Baird, Ann. Mag. Nat. Hist. xi. p. 87. 



Superior antennae flat, consisting of only one articulation. 

 Inferior antennse large, two-branched, each branch having three 

 articulations. Second articulation of anterior branch provided 

 with a very long seta. Eye accompanied with a black spot. 



Gen, 2. Bosmina, Baird, Trans. Berw. Nat. Club, 1845. 

 Superior antennse long, curved, cylindrical, and consisting of 

 many articulations. Inferior antennse large, two -branched, one 

 branch having four, the other three articulations. 



Sp. 1. Bosmina longirostris. PI. IX. B. f. 1. 

 Syn. Lynceus longirostris, Miiller, Entom. 76. t. 10. f. 7, 8. — Mono- 

 culus cornutus, Jurine, Hist. Nat. desMonoc. de Geneve, 142. t. 14. 

 f. 8-10. — Daphnia cornuta, Desmarest, Consid. g^n. Crust. 375 ; 

 Baird, Ann. Mag. Nat. Hist. i. 257. t. 9. f. 15 ; ikf. Edwards, Hist. 

 Nat. Crust, iii. 382.^Bosmina cornuta, Baird, Trans. Berw. Nat. 

 Club. 1845. 



