PARTULA, RAIATEA AND TAHAA. 217 



Godeff., v, p. 207. HARTMAN, Cat. Part., p. 8, with woodcntr 

 Obs. Gen. Part., Bull. Mus. Comp. Zool., ix, pp. 181, 183, 194 

 (excl. raiatensis) . GARRETT, Journ. A. N. S. P. ix, 1884, p. 68, 

 pi. 3, f . 84:.Partula decorticata PEASE, MS. Coll. Pease, 1863. 

 Partula, labiata PEASE, MS. Coll. Pease, 1863. SCHMELTZ, 

 Cat. Mus. Godeff., v, pp. 92, 207. PFEIFPER, Mon. Hel., 

 viii, p. 209. 



It may be distinguished by its elongate-conical form, straw- 

 yellow color, rather shining surface, chink-like perforation, 

 and small oblong obauriform white aperture. The peristome 

 is ivory-white, heavily calloused, the face angularly ridged, 

 strongly labiated within, and armed slightly above the middle 

 with a very prominent tooth, above which the lip is strongly 

 contracted, forming a conspicuous sinus. A very rare variety 

 occurs of a ruddy 'brown color, purple-black apex, and flesh- 

 colored peristome. Examples with a white sutural line are 

 not infrequent and most shells are a little paler below the 

 suture; otherwise it is never ornamented with bands; even 

 the most perfect specimens always have the cuticle more or 

 less decorticated behind the peristome, which suggested the 

 provisional name decorticata. The above notes, slightly modi- 

 fied from Garrett, apply to the typical P. dentifera from 

 Vairahi valley, of which P. labiata Pease (fig. 9) is an exact 

 synonym. In this form a parietal tooth is never developed. 

 The color varies commonly from straw to light greenish yellow. 

 The figured shell (fig. 9) measures, length 21, diam. 11, aper- 

 ture 12 mm. but it is sometimes as small as 19 mm. long. 



Garrett states that north of Vairahi valley, P. dentifera 

 "has migrated into a small adjacent valley, where it is much 

 less abundant, and differs from the type in about half of the 

 specimens having a prominent parietal tooth (which is al- 

 ways absent in examples inhabiting Vairahi) ; otherwise the 

 shells are not dissimilar. ' ' Examples of this dentate race are 

 figured pi. 20, figs. 7, 8. It 'Certainly approaches close to 

 P. imperforata raiatensis. 



P. dentifera is never banded, and the apex, though often 

 yellow, is never rose-colored, as it often is in P. imperforata,. 



