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 Catinella, Pse. 



T. tenuis, fragilis, planulata, depressa, scutellceformis, ovalis ; spira 

 minuta, rudiment alls, immersa, subtus concentrice sulcata ; aper- 

 tura perampla, magnitudinem testa fere ceqimis. 



The type of the above genus is C. 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- 

 stricted. 



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 accres- 

 centes ; apertura posterior contracta, acuta, antice dilatata ; 

 anfr. ultimus postice convolutus. 



The above peculiar type has been heretofore only known as in- 

 habiting the Tahitian Islands, where it is represented by Succinea 

 procera, Gld., and 5 1 . infundibuliformis, Gld. A species was unex- 

 pectedly 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 et te- 

 nuiter notata, rubella aut succineo-rubescens ; anfr. 3, ultimus 

 tumidiusculus, vLv obliquus ; anfr. spirce convexi, apice mammil- 

 lato, sutura valde impressa ; apertura oblongo-ovalis, fere recta, 

 labro incrassato, rufo; columella margine callosa, vix arcuata, 

 plica conspicua. 



Alt. 12, diam. 7\ mill. 



Hab. Insvda Nukuhiwa. 



