116 ANNUAL KEPORT. 



The eyes are large, convex and compound, and are situated on rather large 

 peduncles, which are movable; the mouth consisting of a labrum, a pair of man- 

 dibles and two pairs of jaws. 



The thorax consists of eleven segments, each bearing a pair of branchial feet, 

 which are large and foliaceous, and consist of three joints. The first is the larg- 

 est, and has on its lower edge a semicircular branchial plate, which is furnished 

 with about forty plumose hairs; the second joint of the feet bears on its inner 

 side three projections, each of which sends off long hairs; the third joint is long", 

 bearing plumose setse. 



The abdomen is composed of nine segments, which are devoid of appendages, 

 except the two terminal plates, which are beset on theii* edges with plumose setse. 

 In the female there is an external oviferous pouch. 



The dorsal vessel or heart, commences near the head, and traverses the whole 

 length of the body. When fully grown it is upwards of an inch in length, slen- 

 der, of a cylindrical form, and nearly transparent. The male has a reddish tinge 

 throughout. The tail is of a beautiful red; the basal joint of the prehensile 

 antennse a bluish green tipped at the end with red. The back of the female is 

 bluish, and the ovary brown. 



These are beautiful animals, and may be seen in fine weather balancing them- 

 selves, near the surface of the pools they inhabit, by means of their branchial 

 feet; but when disturbed they strike the water from right to left, and dart away 

 like a fish, to conceal themselves among the weeds at the bottom of the pond. 



GENUS Branchinecta, 



Characters. — Form rather slender, with the medium appendages longest, so as 

 to somewhat resemble Artemia in outline, but larger; male with 

 rather slender, rounded, two-jointed claspers. Egg-pouch much 

 elongated. 



GENUS Eubranchipus. (Verrill.) 



Characters. — Body robust; made with large head and very stout claspers; firs 

 joint of claspers much swoolen, capable of retracting bas^ 

 portion of the second joint into their cavity; second joint stout 

 at the base, in the typical species with a large tooth on the inside, 

 the outer portion .tapering, rather obtuse. Front of head 

 between the claspers bears two thin, flat tapering appendages. 

 Caudal appendages long. Egg-pouch short and thick. 



genU^ Streptocephalus. (Baird.) 



Characters. — Male claspers long, three-jointed, tortuous; terminal point sub- 

 divided more or less into two branches, or bearing slender ap- 

 pendages. Male organs long and slender. Egg-pouch elongate 

 or conical. 



GENUS Artemia. 



Bibliography. — Artemia, Leach, Dist. Sc. Nat., XIV. 



Artemisus, Lamark, Hist. An. S. Vert. (2d edit.) 

 Artemis, r^om^soM, Zool. Res., 104. 



