ON ACANTHOLEBERIS. HD 
Acantholeberis curvirostris was discovered last summer by 
Mr. D. Robertson, in the Isle of Cumbrae in the Frith of Clyde, 
living in some abundance in a small shallow pond about twelve 
feet square, which has been cut out of the sandstone rock, and 
was covered at the bottom with moss and Conferve. Mr. Robert- 
son informs us that though the species seems fond of remaining 
quiety among the weeds, it nevertheless is tolerably active when 
swimming, which it effects with a slight jerking motion, often in 
curves. It has a habit of mounting to the surface of the water, 
and then allowing itself passively and slowly to sink to the bot- 
tom, with its antenne spread out on either side. It rarely re- 
sumes active motion when in its downward course, unless it is 
disturbed. 
A second locality for the species is Crag Lake, Northumber- 
land, where it has been met with, during the present spring, by 
Mr. G. S. Brady. 
Acantholeberis sordida (Lievin). Pl. I. figs. 6-9. 
Acanthocercus sordidus, Lievin, “Die Branch. der Danziger 
Gegend,’’ Neueste Schriften der naturf. Gesells. in Danzig, B. 
iv. p 34, pl. 8. f. 7—12. Fischer, Bull. de la Soc. Imp. des 
Nat. de Moscou, 1854. Leydig, Naturgeschichte der 
Daphniden, p. 199. 
Carapace nearly round, widest below, and slightly truncate on 
the inferior margin, tumid, and having the surface clothed with 
short hair. Anterior antenne largely developed, long, cylin- 
drical. Posterior antenne short and stout; their peduncles 
very large, stout, and powerfully muscular. Both branches very 
short, the separate articulations being scarcely longer than they 
are broad, and the total length of the branches barely exceeding 
the width of the bases of the enormously developed peduncles. 
Upper and four-jointed branch terminating in three plumose 
sete and a long spine, which equals two-thirds the length of the 
basal portion of the sete. Lower and three-jointed branch 
having a seta at the extremity of the first and second joints, and 
three sete and a spine at the termination of the third joint. 
The sete of the first two joints do not differ materially in char- 
