132 BRITISH ENTOMOSTRACA. 



cilia long ; striated or ribbed longitudinally, the ribs 

 rather distant. Beak rather blunt. Eye areolar. 



Superior antennae conical-shaped ; inferior, or raini 

 (t. XVI, f. 4 b], short, the setae also being short ; anterior 

 branch having four, one from second and three from last 

 articulation; posterior branch has three from last joint only. 



Upper part of body rounded, as in Acroperus harpa 



Abdomen (t. XVI, f. 4 c] rather narrow, sinuated near 

 extremity, and serrated for about half its length on the 

 under edge, the serras or teeth at extremity being the 

 largest. Terminating claws long. 



Intestine convoluted once, and nearly a half, but not 

 so distinctly visible as in the other genera.* 



Hab. Ditch near Richmond ; pond at Osterly Park ; 

 and near Hounslow. In the Pease-burn, Cockburnspath. 

 Pool on Bowmont Water, Yetholm, Roxburghshire. 



2. ALONA RETICULATA. Tab. XVI, fig. 3. 



ALONA RETICULATA, Baird, Ann. and Mag. Nat. Hist., ii, 93, t. 3, f.12, 



1813 ; Trans. Berw. Nat. Club, ii, 151. 



In size this is perhaps the smallest of all the species of 

 this family, being still smaller than the Acrop&rus nanus. 



Shell of a quadrangular shape, rounded a little poste- 

 riorly, and nearly straight on anterior margin, which 



* I had some doubts at first as to this being identical with the Nonoculus 

 strialus of Jurine. In his figure the beak is blunter, and the abdoiueii 

 shorter and rounder-shaped than in my specimens, lie gives it the mime 

 xt,-iiitns with a doubt ; and remarks, " if this species be the trnncatus of 

 Midler, as we may presume it is, it must be confessed that its specific name 

 is improper; for the shell is not truncated, it is obliquely striated and 

 strongly ciliated" (1. c., p. 154). It is evident that Jurine could never hu\r 

 seen the truncatus of Miillcr, and the qwtd/rangularis seems also not to 

 have been known to him ; for the difference between this species and the 

 truncatus is so great and evident, that they cannot be mistaken for each 

 other; while the similarity between it and the quadrangularis is so decided, 

 that notwithstanding the slight discrepancies mentioned above, 1 have now 

 little or no hesitation in referring them both to (lie same species. 



