464 MR. HARPER PEASE ON POLYNESIAN LAND-SHELLS. [May 2, 



perist. simplex, continuum, ad anfr. penultimum adnatum aut dis~ 

 junctum, interdum vix porrectum ; anfr. ultimus seepe ad peri- 

 pheriam subangulatus . 

 Animal operculumque gen. Omphalotropis, Pfr.,persimilis. 



The shell of this genus is elongate, sometimes cylindrical, rarely 

 ovate, imperforate, in the species of ovate form narrowly perforate ; 

 aperture ovate, occasionally circular ; peristome continuous, some- 

 times disconnected from the penultimate whorl and very slightly 

 porrected. The last whorl is frequently obtusely angulate on its 

 periphery, of one colour, usually pale yellow or reddish. 



The species furthest removed from the type of Omphalotropis, viz. 

 A. viridescens, T?se., and ventricosa, Hombr., can scarcely he distin- 

 guished from genus Blanfordia, A. Ad. ; those approaching the 

 nearest, vescoi, Dohrn, &c, are of small size, narrowly perforate, 

 abbreviately ovate, but wanting the angulation around the umbi- 

 licus. In the following catalogue they are separated from the 

 typical forms. 



Genus Cyclomorpha, Pse. 



Typus, Cyclostoma flavum, Brod. P. Z. S. 1832, p. 59. 



Testa turbinata, subglobosa, solida, Icevigata aut spiraliter striata, 

 perforata; apertura fere circularis ; peristoma simplex, subin- 

 crassatum, callo tenui continuum. 



Operculum ei gen. Omphalotropis, Pfr. similis. 



The shell of the above genus differs widely from any of the genera 

 of the subfamily Realiea, Pfr. From its similarity to those of the 

 genus Ostodes, Gld., the species have been heretofore included by 

 Drs. Pfeiffer and Gould in that genus. Having received a number 

 of specimens collected alive with the operculum, I discover it to be 

 certainly related to the above subfamily and to Cyclostomince ; while 

 the genus Ostodes belongs to the subfamily Cyclophorince. I also 

 notice that Ostodes cenomphalus, Phil., arranged by Dr. Pfeiffer 

 next to C. flavum, Brod., and included by Dr. Gould in his genus 

 Ostodes, is described as being carinately angulate around the umbi- 

 licus, one of the peculiar characters of the genus Omphalotropis. 



It should be connected with the above genus, serving to confirm 

 its position in the subfamily Realiea, Pfr. 



Its locality is unknown ; the other species inhabit the extreme 

 easterly portion of Polynesia. 



Having had an opportunity of examining the operculum of three 

 species of the genus Ostodes, I extend the description given by Dr. 

 Gould as follows : — 



Genus Ostodes, Gld. 

 Ostodes, Proc. Bost. Soc. vol. viii. 1861, p. 283. 



Operculum tenue, membranaceum, circulare, margine tenuissimo, 

 lacerato ; extusfornicato-convexum, nitidum ; multispirale ; anfr. 

 8-10, lente accrescentes, fere cequales ; sutura linearis, nucleo cen- 

 trali ; apex vix elevatus, papillatvs ; subtus regulariter concava. 



