228 PARTULA, RAIATEA AND TAHAA. 





mellar region 'being, as it were, pressed in towards the aper- 

 ture, nodulous on the inner margin, and subangulated at the 

 base. The parietal tooth is less developed and absent more 

 frequently than in crassilabris. The coloration is the same 

 in the two species. Like the majority of the ground species, 

 it varies in -a greater or less degree in shape and size. Some 

 forms almost exactly simulate P. garrettii, not only in the out- 

 line of the shell, but in the peculiar shape of the aperture as. 

 modified by the columella being pressed inwardly. Occa- 

 sionally examples occur which are so much abbreviated that 

 they resemble P. crassilabris, but may readily be separated by 

 the dissimilarity in the columellar region. 



"My P. pinguis, of which I have seen only a dozen ex- 

 amples, was found under decaying leaves in the mountain 

 ravines, at the head of Vaioara valley. It certainly equals 

 rustica." (Garrett). 



30. P. GARRETTI Pease. PI. 21, figs. 15 to 19. 



The shell is minutely rimate or imperforate, oblong-ovate, 

 solid and strong, slightly shining, lightly marked with 

 growth-striae and minute engraved spiral lines, which are 

 usually more or less obsolete on the last whorl; yellowish, 

 the spire either paler, apex white, or spire pink-tinted with 

 the apex purplish, flesh colored. Suture very lightly impressed, 

 edged with a white line. Whorls 5, very slightly convex. 

 Aperture is oblique, white within. Peristome very narrowly 

 expanded, thick, the face convex or keeled, pure white; in- 

 ternal rib strong. Columella vertical, sinuous, bearing a 

 strong tubercle or node above the middle, its junction with 

 the basal margin angulated. Parietal wall covered with a 

 smooth, transparent callus, not toothed within. 



Length 16, diam. 9 mm. 



Length 14, diam. 9 mm. 



Length 15, diam. 8.5 mm. 



Baiatea : ' ' The specific centre is Vaioara, on the west coast 

 of Raiatea, where it exists in prodigious numbers on bushes. 

 It has spread north and south of its metropolis, and in the 



