Land and Freshwater •Mollusks. 45 



a carnivorous little animal and formidable to the earth worm — is 

 also very local, frequent, I am informed, about Bath, but in many 

 parts of England wholly unknown, of this I was fortunate enough 

 to find a specimen near Kensington, beside a paved and much 

 frequented path; it has been previously recorded as occurring near 

 London. 



Now a few words regarding the method of collecting and pre- 

 serving specimens. Winter and early spring afford to the collector 

 the best specimens, because the shells are matured, the portion 

 next the mantle, where the growth takes place, is consolidated, 

 and the process of cleaning and preserving is more sure ; on the 

 other hand, the present season gives better opportunity of seeing 

 the animals, and of collecting examples at different stages of 

 growth. To show a species well, a progressive series from the 

 youngest stage, the egg if possible, to the matured shell should be 

 collected, and such a series is best exhibited fastened down in 

 order on a card ; the animals must be removed, and, if nothing 

 more effectual is at hand, a little camphor can be used to aid in 

 preserving specimens from which it has been impossible to extract 

 the whole animal. Some collectors put gum over their specimens 

 to imitate the fresh appearance they have when damp, but the 

 effect is artificial and unsatisfactory ; a little oil may, however, be 

 rubbed on some shells with advantage, as it prevents the epidermis 

 cracking, and tends to preserve them. In the case of shells having 

 an epiphragm — that is, a temporary winter covering to close the 

 mouth, as the Helix Pomatia — this epiphragm should be preserved 

 and replaced when the animal is removed. Of those having an 

 operculum — that is, a permanent moveable plate attached to the 

 body of the animal with which it completely shuts itself into its 

 shell — this operculum should be carefully preserved ; it is seen in 

 the common Bythinia tentaculata, abundant in the water in Harrow 

 Park. In collecting the smaller Helices, and generally all small 

 specimens, note the colour of the animal at the time, as this may 

 aid identification. For the minute species, as Helix pygmaea and 

 the various kinds of vertigo, the most ready plan is to gather the 

 moss, &c., which they frequent, and spread it on white paper, or to 

 place small pieces of damp decayed twig with loose bark — some- 

 times a dead worm near it — in the localities that seem likely to 

 afford specimens, and thus to snare them. Under stones in damp 

 places, decaying brickwork, bark of old mossy trees, leafy hedge- 

 rows, among the weeds at the base, are the spots that repay search 

 on such soil as the neighbourhood of Harrow ; while streams, 

 canals, still waters, even the very smallest ponds have their species ; 

 the most insignificant pool of water, if not temporary, should be 

 examined. 1 have found the pretty Pisidium nitidum in a pond 



