PONTIGULASIA COMPRESSA. 



63 



also near Criccieth and in the Sychnant Pass, North 

 Wales. South Devon, 1864 (H. J. Carter). Loch 

 Ness (D. J. Scourfield). Killough, Co. Wicklow, 

 Ireland (/. Hopkinson). 



This species can hardly be considered rare in 

 Britain. It is of frequent occurrence in the localities 

 mentioned, and doubtless in most situations of a 

 similar character throughout the country. It seems 

 to flourish indifferently in Sphagnum-bogs, in damp 

 ditches where Sphagnum is found (as in the neigh- 

 bourhood of Criccieth), and in the deep waters of 



FIG. 72. Lateral views (narrow and broad) of Pontigulasia compressa. 

 After Carter, loc. cit. x about 280. //. " Dark, collar-like mark at 

 the base of the neck of the test" (Carter). 



lakes. It is recorded by D. J. Scourfield from Loch 

 Ness, Scotland, at depths of 272 and 680 feet ; and 

 Penard finds it in Lake Leman, Geneva, at 20-40 

 metres depth. Examples taken at Dunham, Cheshire, 

 in 1903, were blackish opaque, and so thickly incrusted 

 with sand-grains as almost to obscure the constriction 

 and render identification difficult. Individuals were 

 very active, and might have been mistaken for coarse 

 Difflugiss but for the unequally compressed test. 



The species was first observed by Carter at 

 Budleigh-Salterton, in " heath-bog water," among 



