The number of estuarine species which have a place in our works devoted to British land and freshwater snails is very few, and the majority, moreover, are confined to the margins of the tidal rivers in the south of England. Thus _Assiminea Grayana_, _Hydrobia ventrosa_, and _H. similis_, live on the mud banks beneath the shade of sedges and rushes, skirting the Thames below Greenwich. To gather these small shells singly is a tedious operation; but if a thin piece of flat wood, or other substitute as the ingenuity of the collector suggests, be used to scrape lightly over the surface of mud, transferring the mass to the _dredger_, and washing in water, a number of specimens sufficient to stock every private cabinet in the country may be obtained in a short space of time. For the third initiatory excursion our steps were directed inland, and as we proceeded the hedgerows, mossy banks, and margins of watercourses were diligently searched, finding a _Helix_ here, a _Pupa_ or a _Succinea_ there. Gaining the woods, we turn over the damp leaves, grub under the clumps of ferns and wood-rushes for small Helices, Pupæ, and the like; scan the trunks of the trees for the climbing _Clausiliæ_, _Bulimi_, and _Helices_, not unmindful that each little dirt-like mass is probably a _Bulimus obscurus_, which, by covering its shell with mud, thus exhibits a protective faculty, and often escapes detection. Raise the rotting bark for _Balia_; lift the stones at our feet, or roll away a log for _Helicella_, and other small shells which usually live in such situations. From all this we learn that each species affects certain stations, and therefore, with the knowledge of the circumstances in which they are found, we may set out with some definite idea as to what we are likely to meet with; and, in consequence, when to collect and where to collect are regulated by the unvarying habits of the objects of our search. Now, a large portion of the life of most land snails is passed in a state of sleep. Those living in open situations are inactive during the heat of a summer's day, and when there is continued drought; but on the first shower, or after the fall of dew at night, they recover and move about in search of food. Cold acts much in the same way as heat, and with the fall of the leaf they retire to winter quarters in crannies of rocks, crevices of walls, under heaps of decaying vegetation, &c., or bury themselves in the soil, there to hybernate till the genial showers of spring awaken them. The best time of the year for collecting is in the autumn, when the shells are full-grown. Those collected in spring have lost much of their original beauty by exposure to the rains and cold of the winter months.