MACROTHRIX. 
103 
Genus 3 — Macrothrix.* 
Macrothrix, Baird, Ann. Mag. Nat. Hist., xi, 87, 1843, and xvii, 412 ; 
Trans. Berw. Nat. Club, ii, 149. 
Daphnia, M. Bdwards, Hist. Nat. Crust,, iii, 384. 
— Muller (?), Entomost. 
Lynceus, Besmarest, Cons. gen. et part. Crust,, 370. 
Monoculus, Jurine , Hist. Monoc. Geneve. 
Acanthocercus, Schodler, Erichs. Archiv, 1846. 
<9 
Character. — Superior antennae flat, one-jointed, pen- 
dulous from the beak. Filament from extremity of first 
joint of anterior branch of inferior antennae much longer 
than any of the others. Eye accompanied with a black 
spot. 
1. Macrothrix laticornis. Tab. XV, fig. 2. 
Daphnia curvirostris (?), Muller, Entomost., t. 13, f. 1, 2. 
Monoculus laticornis, Jurine, Hist. Monoc., t. 15, f. 6. 
Lynceus laticornis, Besmarest, Cons. gen. part. Crust., 376. 
Macrothrix laticornis, Baird, Ann. Mag. Nat. Hist., xi, 87, t. 2, 
f. 9, 10; Trans. Berw. Nat. Club,ii, 149. 
Acanthocercus curvirostris (?), Schodler , Erichs. Archiv, 1846. 
The shell or carapace is of an oval shape, transparent, 
colourless, smooth, strongly ciliated on anterior margin^ fomc't&O n* 
The inferior antennae or rami are strong and large 
(t. XV, f. 2 a). The posterior branch has four setae ; three a, rfJuc 
from the extremity of the last articulation, and one from the 
extremity of the second. The anterior branch has five setae, 
four disposed as in the posterior branch, and one very long, 
from the extremity of first articulation. Superior an- 
tennae pendulous from the extremity of the beak, rather 
broad, becoming narrower at their base, and furnished 
with three short setae at their extremities. 
Eye large, distinctly areolar, and having an accom- 
panying black spot near the root of the superior antennae. 
* M aKpog, long; and 0pi%, a hair. 
