TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 39 
late walls. In adults there are eight flat whorls, the last three subconcave, and the 
aperture is a nearly equally four-sided square. 
Var. PICEA, Garrett. 
This variety, which I have distributed to my correspondents under the name of 
Pitys picea, differs none from the type, except in being smaller and the parietal wall 
unilaminate. The aperture is also vertically narrower. 
Not infrequent on the west side of Raiatea. 
E. ogowus, Gould. 
Helix obolus, Gould, Proc. Bost. Soc. Nat. Hist., 1846, p. 175; Expl. Ex. Shells, p. 53, fig. 50. 
Pfeiffer, Mon. Hel., i, p. 187. 
Endodonta obolus, Albers, Die Hel., ed. 2d, p. 90. Pease, Proc. Zool. Soc., 1871, p. 474. 
Pitys obolus, H. and A. Adams, Gen. Moll., ii, p. 114. 
Patula obolus, Schmeltz, Cat. Mus. Godeff., iv, p. 72. Paetel, Cat. Conch., p. 93. 
Helix acetabulum, Pease, Proc. Zool. Soc., 1861, p. 242. Pfeitfer, Mon. Hel., v, p. 222. 
Endodonta acetabulum, Pease, Proc. Zool. Soc., 1871, p. 474. 
Pithys? celsa, Pease, Jour, de Conch., 1870, p. 396. 
Endodonta celsa, Pease, Proc. Zool. Soe., 1871, pp. 455, 474. 
Helix celsa, Pfeiffer, Mon. Hel., vii, p. 260. 
Patula Barffi, Garrett, Schmeltz, Cat. Mus. Godeffr., v, p. 93. 
Patula intermixta, “ Mousson,” Schmeltz, Cat. Mus. Godeff., v, p. 93. 
This variable species, which is confined to Raiatea and Huaheine, is plentiful and 
widely diffused over the two islands. 
Dr. Gould’s habitat, “ Taheiti,” is undoubtedly wrong. Having personally explored 
every valley on ‘Tahiti and Moorea, I did not find a single example of this type of 
Helices. His specimens were probably from Raiatea. Dr. Gould describes it as 
follows :— 
“'T. parva, discoidea, deorsum compressa, supra planulata, infra concava, radiatim 
minutissima et inequaliter striata, fusco-ferruginea, piceo tessellata; spire anfr. 54, 
supra excavati, ultimus superne costato-carinatus; apertura subrhomboidea, fauce 
lamella unica secundum anfractum penultimum volventi. Lat. 4, alt. DON 
(Gould). 
The above description accords well with the shells under consideration, and the 
supra excavata”” agrees better with the Raiatea shells than those from Huaheine, 
But the above author’s reference to Plunorbis vortex as similar in shape renders the 
identification beyond doubt. 
Tam fully convinced that Pease’s wcetabulum is specifically the same as Gould’s 
species. 
Mr. Pease’s diagnosis, which is rather obscure, I reproduce :— 
*'T. parva, planorboidea, superne leviter convexa vel plana; umbilicus amplus, 
eyathiformis ; utrinque subtiliter radiato-striata, ad peripheriam et umbilici marginem 
