_Helix striata_ (Draparnauld)[13] is truly polymorphic; and its various forms have been described under various specific names. It abounds in the calcareous hills of Provence and Languedoc, disappearing in the alluvial lowlands and equally in the upper levels at about 800-1,000 m. From this district it extends through regions of similar altitude over a great part of France (details given). Locard in his monograph of this group, which he calls collectively the group of _Helix Heripensis_, tabulates 27 distinct named forms. The characteristics in which these forms differ have been reckoned as 17, and as several of these vary in degree of development, the number of modes may be increased to 109. For practical purposes however Coutagne considers that the various developments of 7 characteristics in their several combinations are enough to express the various forms, and he gives examples of this method of definition. As he observes, though names may be required to define the modes, no one need be alarmed at that, for the same names of modes will be applicable to a great range of distinct species, and the formulae expressing their combinations will replace the varietal names. This particular example of polymorphism is but little limited by locality. Occasional colonies present some special physiognomy which may in a given place seem almost invariable, though in this very respect the colonies found elsewhere may be highly variable, but such limitations are exceptional for _H. striata_. Some distinct and obvious susceptibilities to the influence of soil and climate are however noticeable. For example on siliceous ground the shells are thinner, while on calcareous soils they are thicker; similarly those from the Northern districts attain a larger size than those from further South. Moreover those subjected to curtailed development, whether from drought, heat or cold often show a shortening of the spire. In contrast with this case Coutagne describes the varieties of _Helix caespitum_, which he says are for the most part localised, quoting many illustrative cases. Another remarkable case in which locality plays a curious part is provided by the two species _Helix trochoides_ and _pyramidata_. In France generally they are distinct enough from each other, _trochoides_ being smaller and having a characteristic keel. Coutagne says that after having collected these species from more than a score of localities he came upon a colony of _trochoides_ on the island of Pomègues in which the shells were relatively enormous, most of them having only a slight keel, and a few none at all. On the other hand he received a consignment of _pyramidata_ from four localities in Sicily, all small, and one of them exactly like the _trochoides_ from Pomègues. Judging by the samples received from Sicily, _trochoides_ is there not more variable than it is in Provence, while the Sicilian _pyramidata_ is protean.