ALONA. 
131 
than in harjpce; anterior branch has four setae, one sprin g- 
ing from the se cond , and three from the extremity of last 
joint only. 
Abdomen has a gibbon s projection about the middle of 
the lower margin, and is serrated at extremity. Intestine 
convoluted, having one turn, and nearly half another. 
One ovum. 
In size, this species is about the smallest of the family 
that I have met with. 
Hah . — Pond at Norwood Green ; and near Southall, 
Middlesex, June 1841. Rare. - 
Genus 5 — Alona. 
Lynceus, Muller , et auctorum. 
Alona, Baird, Ann. and Mag. Nat. Hist., ii ; Trans. Berw. Nat. Club, ii. 
Character . — Shell quadrangular-shaped, grooved or 
striated longitudinally. Inferior antennae or rami short. 
Beak blunt, and nearly erect. 
1. Alona quadrangularis. Tab. XYI, fig. 4. 
Lynceus quadrangularis, Muller, Zool. Dan. Prod., No. 2393, 1776 ; 
Entomost., t. 9, f. 1-3. 
Latreille, Hist. Crust., 208. 
Baird, Trans. Berw. Nat. Club, 100. 
M. Bdwards, Hist. Crust., iii, 388. 
Koch, Deutsch. Crust., h. xxxvi, t. 1 5. 
Monoculus qdadrangulus, Gmelin, Syst. Nat., 3008, No. 61. 
— Manuel, Enc. metli., viii, 733, t. 268, 
f. 18-20. 
Monoculus quadrangularis, Fabricius, Ent. Syst., ii, 498. 
Monoculus striatus (?), Jurine, Hist. Monoc., t. 16, f. 1, 2. 
Alona quadrangularis, Baird, Ami. and Mag. Nat. Hist., ii, 92, t.3, 
f. 9-11,1843; Trans.Berw.Nat. Club, ii, 151. 
Nearly quadrangular- shaped. Shell transparent, of a 
deep-brown colour ; strongly ciliated on anterior margin, 
