_Bulimus_ and _Bulimulus_, the former genus being peculiar to S. America and the adjacent islands, are largely represented, the former in the three groups _Borus_, _Dryptus_, and _Orphnus_. These attain their maximum in Peru, with 25 species, but Venezuela and Colombia have as many as 17. _Bulimulus_ has been subdivided into a number of groups, _e.g._ _Drymaeus_, _Mesembrinus_, _Thaumastus_, _Mormus_, _Scutalus_, with many others,--the exact scientific limits of which are not easily discernible. It must suffice here to state that Peru seems to be the headquarters of the group with about 190 species (which probably may well be reduced), Ecuador having about 70, and Venezuela and Colombia between 80 and 90. [Illustration: FIG. 234.--_Rhodea gigantea_ Mouss., New Grenada.] Two very remarkable forms belonging to the Pupidae, _Anostoma_ (Fig. 154, p. 248) and _Tomigerus_, occur in Venezuela, the metropolis. _Rhodea_, another very peculiar shell (Fig. 234), whose exact family position is uncertain, is peculiar to New Grenada. The land operculates are few in number, and in Bolivia almost disappear. They belong principally to _Neocyclotus_ (of which 11 species occur in Venezuela and Colombia) and _Helicina_ (10 species in the same district), besides the stragglers already mentioned from West Indian sources, and a few _Cyclophorus_. _Bourcieria_ is a form of _Helicina_ peculiar to Ecuador. _Ampullaria_, with _Ceratodes_, a peculiar planorbiform sub-genus, and _Hemisinus_, form the bulk of the fresh-water operculates. _The Galapagos._--Thirty-four species of land Mollusca, all peculiar, are known from these islands; 25 of these are forms of _Bulimulus_. There are no Helicidae, one each of _Hyalinia_, _Leptinaria_, and _Helicina_, and two _Pupa_. The _Bulimulus_ are mostly of the group _Nesiotis_, and in their brown colour bear some outward resemblance to the dark _Achatinella_ of the Sandwich Is., living as they do mostly under scoriae on the ground, and not on trees. In type, however, they appear to be derived from Chili and Peru, rather than from the parts of S. America immediately contiguous. Another section (_Pleuropyrgus_ 2 sp.) closely resembles a marine _Chemnitzia_. The islands are all volcanic, and are probably not the result of subsidence; thus the existing species are not to be regarded as the relics of a more widespread fauna, but as a new set of inhabitants.