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Show 644 MR. HARPER PEASE ON THE [Dec. 9, the sternum, costal process, and the underside of the marginal shield is white, there being two small round black spots on the underside of each of the five front marginal shields. The head and neck are beautifully marked with very regular pale streaks, but there is no spot behind the eye, and no ring round the margin of the ear. This indicates the existence of a very distinct species; and Dr.Giinther thinks that it is the young state of the Emys grayii, which he has lately described (see anted, p. 504) from the adult shell, without the animal. The Mauremys fuliginosa (antea, p. 500) has the markings on the head and neck somewhat similar to those of Emys flavipes, but sufficiently distinct to define this species, which is also at once known by the depressed and nearly uniform black shields of the shell. 12. O n the Classification of the Helicterince. By H A R P E R PEASE, C.M.Z.S. From a history of the genus Helicter which I published in this Society's ' Proceedings' (1862, p. 3) it appears that it was first named and described bv Ferussac in 1821*, and that this term con-sequently takes precedence oi Achatinella (Swains.), 1828t. I now propose to elevate it to the rank of a subfamily, and to distinguish the several groups of species which it comprises by generic names. They are as distinct, as strictly definable, and vary even more widely than those of any other subfamily of land shells. From the difference in their habits and stations, we may also expect to find the animals to vary correspondingly when examined. Had the several species been received in Europe at different times without their locality being known, they would have been distributed over five or six old established genera. They are, in fact, a natural subfamily, confined to the Hawaiian Islands, representing within themselves, by the forms of their shells, several genera inhabiting distant localities, in a similar manner to several other genera inhabiting Polynesia, such as Pitys, species of which have been classed bv authors with the European genus Patula, although the animals of the two are widely distinct. I will not notice at present the several attempts made of late years to dismember the Helicterince and unite several species to foreign genera, such as Balea and others, as I am convinced that the "Testaceous classification" adopted by those authors will be abandoned so soon as the result of the researches of persons now permanently located at many localities in the tropics and elsewhere, formerly but rarely visited and hastily explored, are made known. As to the distribution of genera and species over the several islands of the group, I remark generally that, with the exception of the genus Leptachatina (the species of which are small and of simple * Tableau Svst. des An. Mollusques, 1821, p. 5G; Yoy. par M . de Freycinet 1824, p. 475. t Quarterly Journal of the Royal Institution, 1828, p. 81. |
