51 
ot ) the centre of the foot, and covered with a thin mantle, 
' v, th a thickened edge, which is ilself covered with an ex- 
ter nal spiral shell, which has a plaited pillar in all its ages.” 
CARYCH1UM. 
GENERIC CHARACTER: The shell spiral, thin, conic 
ovate; mouth oblong, longitudinal, two or three toothed, 
compressed, rather oblique, rounder at each end ; peris- 
tome interrupted, thickened, and rather reflexed. 
MINIMUM, Helix Carychinm. Turt. Lin. Turbo C. 
Mont. Test. Brit, vol. 2, p. 339. C. M. Flem. Brit. An., 
p. 271. Gray’s Turt., p. 221, fig. , p. 219. Not un- 
common. 
CYCLOSTOMA. 
GENERIC CHARACTER : Shape of the shell variable ; 
w horls of the spire cylindrical; aperture round, regular ; 
'he margins circularly united, or reflected by age. An 
operculum. 
Mr. Gray constituted this a family under the name of 
y elostomidae. His generic character of Cyclostoma is : 
s 'ell ovate, spiral; mouth simple, united all round; oper- 
Cl dum of a few flat whorls, with a simple shelly internal 
c ° at : the foot divided into two parts by a longitudinal 
ff D tral groove. 
• ELEGANS. Turbo Tumidus. Turt. Lin. Pen. Brit. 
2°., vol. 4, pi. 32, fig. 110. T. Elegans. Mont. Test. 
Evit., vol. 2, p. 342. C. E. Flem. Brit. An., p. 257. 
Cray’s Turt., p. 275, and fig. 1, 2, 3, p. 273, and pi. 7, 
“g- 75. I have only obtained a specimen, by gift, from 
the west of the county. 
LIMN AS AN A. 
The shell spiral, the outer surface mostly smooth; right 
ar gin of the aperture acute, and not reflected. 
.. Mr. Gray denominates the family Limnaeadae; and observes 
,, , at the forms of the shells vary much in different genera, 
s : lQ . ®hape and form but the group is natural, from the 
hilarity of the animals. 
LIMNLEUS. 
Generic CHARACTER: The shell ovate, thin, dex- 
r M> transparent, spiral; mouth ovate, with a single, 
b hque plait on the middle of the column, running into 
l' e axis: Gray; who observes, this genus is known from 
i "'phipeplea and Physa by the inner lip not being ex- 
uded over the body whorl of the shell; and from Ap- 
ples by the shell being dextral and having the pillar 
EEREGER. Helix Peregra. Turt. Lin. H. Putris. 
ren * Brit. Zo., vol. 4, pi. 86, fig. 137. li. P. xMont. Test. 
