Dr. W. Baird on British Entomostraca. 89 



and one long one from first and second articulations. These 

 setae are finely plumose, like those of Daphnia pulex, and 

 jointed about the middle of their length. Eye large, contained 

 in an infundibuliform tube, areolar, areolae about twenty in 

 number. The accompanying black spot is remarkably small, 

 situated almost directly under the eye instead of in front of 

 it, and is somewhat of a square shape. Intestine convoluted, 

 having one complete convolution and nearly a half. The 

 lower part of abdomen or body of animal has a lobe springing 

 out from its edge like a spur. Setae at joint of tail finely plu- 

 mose and jointed at about half their length. Tail very broad, 

 lamellar, densely and strongly serrated on lower edge, sinuated 

 deeply on anterior margin, and terminating in two stout claws 

 and two small ones. Antennae are stout solid bodies, some- 

 what conical in shape, slightly curved and terminating in six 

 short spines, each of which gives out a fine seta or bristle. 

 They are not possessed of much motion. The mandibles are 

 strong, rounded towards extremity, which is possessed of 

 sharp teeth. The first pair of feet consist of a strong fleshy 

 body strongly ciliated on upper edge, and terminating in five 

 long and strong filaments, which generally project outside the 

 shell. The other feet consist of broad plates with the branchial 

 apparatus attached, and resemble a good deal those of the 

 Daphnice. The motion of this species is peculiar ; it generally 

 lives at the bottom of the vessel in which it is kept, and when 

 disturbed it bounds up by rapid short motions in a curved sort 

 of line, and then returns in the same manner to the place from 

 where it rose. It is very heavy and slothful compared with 

 the other genera, and I have frequently turned it over two or 

 three times before it moved. 



Hab. Not uncommon in ponds and ditches near Isleworth ; 

 u in Yetholm Loch, and in a pond on Beaumont water." — 

 Trans. Berw. Nat. Club. 



3rd Subgenus. Chydorus, Leach. "Nearly spherical in 

 shape. Beak very long and sharp, curved almost into the 

 shape of a crescent. Rami very short." 



1st Sp. Chydorus sphcericus. PL II. fig. 11 — 13. 

 Syn. Lynceus sphsericus, Mull. Zool. Dan. Prod. no. 2392 ; Entom. 

 71. t. 9. f. 7 to 9. — Monoculus infusorius, Schrank, En. Ins. Just. 

 536. no. 1 1 19 ; Eichhorn* ? Beyt. t. 3. f. D. — Mon. sphaericus.Lmrc. 

 Gmel. 3008. no. 60 ; Manuel. Enc. Mtih. Hist. Nat.vu. 732. t. 268. 

 f. 15 — 17 ; Fabricius, Ent. Syst. ii. 497. — Lynceus sphaericus, 



* Perhaps this may be a new species. Miiller quotes this figure of Eich- 

 horn for his Lyn. trigonellus, but it appears to me to be quite distinct. It 

 resembles the sphcericus in shape, except that the inferior extremity of the 

 shell is pointed. Should it prove a new species, I should propose to name it 

 Chydorus Eichhorni. 



