136 BRITISH ENTOMOSTRACA. 



3. Pleuroxus hamatus. Tab. XVII, fig. 5. 



Ltnceus hamatus, £aird,Tr&ns. Berw. Nat. Club, 100,t.2,f.l8,1835. 



Pleuroxus hamatus, Baird, Ann. and Mag. Nat. Hist., ii, 94, t. 3, 



f. 14, 1843; Trans.Berw. Nat. Club, ii,151. 



About half the size of the precedmg species. 



Shell truncated anteriorly, and ciliated ; extremely trans- 

 parent ; upper part gibbous. 



Beak blunter and stronger than in trigojiellm. 



Inferior antennae or rami with three setse in each 

 branch. 



Abdomen gibbous, not serrated, terminated by two 

 claws or hooks. 



First pair of feet large, each furnished at extremity with 

 a strong claw or hook turning upwards. 



Intestine convoluted,* 



Hah. — Yetholm Loch, and pool on Bowmont Water, 

 near Yetholm Bridge, Roxburghshire, July 1835. 



Genus 7 PERACANTHA.f 



Lynceus, Miiller, et audorum. 



Peracantha, Baird, Ann. and Mag. Nat. Hist., ii. 



Character. — Oval-shaped ; the lower extremity of shell 

 slightly curved backwards, and, as well as the upper ex- 

 tremity of anterior margin, beset with strong, hooked 

 spines. Beak sharp, curved downwards. 



* I have only once met with this species. It may perhaps be the male 

 of trigonellus, the cheliform nature of the first pair of feet having a consi- 

 derable resemblance to the structure of that organ in the male Daphnia, 

 and more especially in the male of the Estlieria, as represented by Joly in 

 his description of the /s«2i!/-« cyc/«c?02rfes, 'Ann. Sc. Nat.,' 2d series, xviii, 1843. 



i" Prom vepag, extremity ; and aicavOa, spine. 



