48 



This genus, which seems perfectly natural, is adopted by 

 Mr. Gray from Mountfort; and is to be regarded as an 

 amendment of the system of Lamark. 

 Z. ROTUND ATUS. Helix Radiata. Mont. Test. Brit., 



vol. 2, p. 432. H. Rotundata. Flem. Brit. An., p. 263. 



Z. R. Gray's Turt. p. 165, pi. 5, fig. 44. Common. 

 Z. CELLAR1US. H. Nitens. Turt. Lin. H. Lucida. 



Mont. Test. Brit., vol. 2, p. 425. Z. C. Gray's Turt., 



p. 170, pi. 4, fig. 40. 



Montagu gives the following account of what he supposes 

 to have been a variety of this species. Those found at 

 Newbury on peat were dark, and never exceed a quarter 

 of an inch in breadth. " That found under water was 

 crawling upon Brooklime, and was considerably larger ; it 

 was in a water course, or drain to a swamp, near Penzance 

 in Cornwall. These however appear from their shape to be 

 the same, but whether they are really distinct from the 

 Lucida (Z. C.) or only varieties, the observations of future 

 Conchologists must determine. We do not recollect whether 

 the animal we found under water was of the true aquatic 

 kind, or whether it possessed four retractile tentacula, and 

 had by accident fallen into that element ; but we never 

 before or since, found one so large, so extremely thin and 

 pellucid, or of so light a colour. 



* Z. CRYSTALLINUS. Gray's Turt., p. 17G, pi. 4, fig. 42. 



Not common. 



Z. ALLIARIUS. Gray's Turt., p. 168, pi. 4, fig. 39. 

 Scarcely common. 



SUCCINEA. 



GENERIC CHARACTER: The shell oval, oblong, thin, 

 with a short conical spire and rapidly enlarging whorls 

 ending in a large, longitudinal, oblique mouth, with the 

 peristome disunited behind ; pillar smooth, with an imper- 

 forated axis. 

 The genus is known from Helix and Zonites by its oblong 



shape, and from Limnaeus by there being no mark of an oblique 



fold on the pillar. 



* S. PFEIFFERI. Gray's Turt. p. 178, pi. 6, fig. 74. 

 Scarcely rare. I found some specimens in a small drip- 

 ping stream, among multitudes of Limnaeus Pereger. 



S. PUTRIS. Helix. P. Turt. Lin. Mont. Test. Brit., vol. 

 2, p. 376. S. P. Flem. Brit. An., p. 276. Gray's Turt., 

 p. L78, pi. 6, fig. 73. 1 entertain little doubt of its being 

 Cornish, but I do not find it within the sphere of my 

 research. 



BULIMUS. 



GENERIC CHARACTER: The shell oblong or turreted, 

 the spire ending rather acutely, with the last volution larger 



