THE COOK'S OR HARVEY ISLANDS. 389 



costulate striae, rounded (rarely subangulate) body whorl, and by the numerous 

 internal laminae both in the palate and on the parietal region. The umbilicus is 

 very rarely closed, and, with few exceptions, is smaller, and the walls are more 

 precipitate than in Patula. The aperture is also more contracted and more 

 vertical. 



Prof. Mousson unites them with Endodonta, a distinct genus confined to the 

 Sandwich and Society Islands. Psetel and Schmeltz have affiliated them with 

 Patula, the former, however, recognizing Etidodo7ita as a distinct subgenus, but 

 makes it less natural by having included the remarkable group of which Helix 

 bw'satella, Gould, is the type, and which Mr. Pease referred with a doubt to Pitys. 



P. ZEBRiNA, Garrett. 



Fitys zebrina, Garr., Proc. Phil. Acad. Nat. Sci., 1813, p. 234, PL 3, fig. 66. 



Of this rare species I obtained only half a dozen specimens, which were found 

 in the same valley with Patula decorticata, var. Otarece. Its most obvious charac- 

 ters are the conspicuous stripes and spots on a pale ground, and the distant thin 

 membranous riblets which in adults are more or less lacerated. The parietal 

 region is furnished with two and the palate with three or four laminae. 



P. MULTiLAMELLATA, Garrett. 



Pitys muUilamellata, Garr., Amer. Jour. Conch., 18T2, p. 230, PL 19, fig. 25. 



Patula muliilamellata, Schmeltz, Cat. Mus. GodefF., v. p. 94. 



Helix multilamellata, Pfeifler, Mon. HeL, vii. p. 519. 



Not uncommon, and obtained in two separate valleys on Earotonga, It is 

 quite distinct from any other South Polynesian species. The numerous narrow 

 whorls (6 J to 7), deep sutures, vertical umbilicus, thin crowded riblets, and numer- 

 ous (11) internal laminae will readily distinguish it. 



P. IMPERFORATA, Pease. 



Pithys imperforata, Pease, Jour, de Conch., 1810, p. 394. 



Pitys imperforata, Pease, Proc. Zool. Soc, 1871, p. 458, 414. 



Patula Aitutakiana ("Mouss."), Schmeltz, Cat. Mus. Godeff., v. p. 94. 



Helix imperfo7-ata, Pfeiffer, Mon. HeL, vii. p. 256. 



A very abundant species, peculiar to the island of Aitutaki. It may be easily 

 distinguished by its imperforate base, small, very thin crowded costulate striae, and 

 numerous internal laminae, of which there is one or two on the parietal wall, and 

 very frequently with several elevated striae which run parallel with the laminae. 

 On the base and palate the laminae range from three to five. The young shells are 

 also imperforate. 



