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Show 1871.] MR. HARPER PEASE ON POLYNESIAN LAND-SHELLS. 459 lonyx; and the other is distinct both as to shell and animal. They are as follows :- Genus C A T I N E L L A , Pse. T. tenuis, fragilis, planulata, depressa, scutelleeformis, ovalis; minuta, rudimentalis, immersa, subtus concentrice sulcata ; apertura perampla, magnitudinem testce fere eequans. The type of the above genus is G. rubida, Pse. (Journ. de Conch. 1870, p. 97), to which should be added Succinea explanata, Gld., both 'inhabiting Kauai, to which island the genus appears to be re- S^Tlct-GCl " The animal of the genus Omalonyx, inhabiting South America, is described as being semiaquatic in its habits, being found in marshes and dying when removed from the vicinity of the water. The habits of the species of the above genus are quite the reverse. They are strictly arboreal, living on the leaves of banana and other low bushes, and dying when washed by heavy rain down into the axils of the leaves holding water. The shell is attached to the animal by a ligament, for which there is a groove provided around the underside of the spire. It is but loosely attached, and may be removed from the animal while living, without apparent injury. Having unfortunately lost my notes of the animal, its description must be deferred. Genus TRUELLA, Pse. Typus, Succinea elongata, Pse., Journ. de Conch. 1870, p. 96. T. elongata, gracilis, tenuis; spira elongata; anfr. celeriter accrescentes; apertura posterior contracta, acuta, antice dilatata; anfr. ultimus postice convolutus. The above peculiar type has been heretofore only known as inhabiting the Tahitian Islands, where it is represented by Succinea procera, Gld., and S. infundibuliformis, Gld. A species was unexpectedly discovered on the island of Kauai during the past year, in which the peculiarities of the genus are the most strongly expressed, and which I adopt as the type. The shell is elongate, slender posteriorly, spire elongate, whorls rapidly enlarging; aperture contracted posteriorly by the convolution of the last whorl. _ . The animal is slender, tentacles small, cylindrical, gradually tapering to a slightly enlarged tip. SUCCINEA MAMMILLATA, Pse. T tenuiuscula, suboblique ovata, striis incrementi confertim notata, rubella aut succineo-rubescens; anfr. 3, ultimus tumidiusculus, vix obliquus; anfr. spirce convexi, apice mammil-lato sutura valde impressa; apertura oblongo-ovahs, Jere recta, labro incrassato, rufo; columella margine cullosa, vix arcuata, plica conspicua. Alt. 12, diam. 71 mill. Hab. Insula Nukuhiwa. |