1887.] mollusks of the viti islands. 171 



8. Microcystis perpolita. 



Nanina {Microcystis) perpolita, Mousson, Journ. de Conch. 18G9, 

 p. 326, pi. 14. fig. 1; 1870, p. 113; 1871, p. 8, var. solida ; 

 Schmeltz, Cat. Mus. Godeff. v. p. 90. 



Helicopnis perpolita. Pease, Proc. Zool. Soc. 1871, p. 475. 



Helix perpolita, Pleiffer, Mon. liel. vii. p. 65. 



This species was found by Dr. Giiiffe on Viti Levu. It also 

 inhabits Tonga and tiie Samoa Islands. 



It is a convexly dej)ressed, pellucid, highly polished, yellowish 

 horn-coloured species Avith 4^ whorls. 



9. Microcystis stearnseana, sp. nov. 



Shell small, imperforated, depressedly globose, pellucid, smooth, 

 shining, luteous horn-colour ; spire convexly rounded, apex de- 

 pressed ; suture linear, narrowly margined ; whorls 5, flatly convex, 

 last one not descending in front, rounded, base convex ; aperture 

 nearly vertical, roundly lunate ; peristome straight, acute, regularly 

 curved, margins remote, not converging ; columella with a white, 

 prominent, nearly horizontal tooth-like fold ; within the base of the 

 aperture, a short distance from the margin, are two sublamelliform 

 white teeth, the upper one the larger, crest- like, the smaller one close 

 to the coluiiiellar fold. 



Major diam. 3, height 2 millim. 



Hab. Viti Islands. 



Several examples found beneath rotten wood at Vanua Balavo, 

 and a few were obtained under dead leaves at Uea or Wallis 

 Island. 



It is closely allied to Nanina {Gastrodonta) eiisifera, Mousson, 

 a Samoan species, which is smaller, more depressed, the body-whorl 

 being subangulated and more depressedly rounded. I name this 

 singular species after my friend R. E. C. Stearns, Esq. 



Genus Trochonanina, Mousson. 

 1. Trochonanina samoensis. 



Nanina samoensis, Mousson, Journ. de Conch. 1865, p. 165. 



Helix samoensis, Pfeiffer, Mon. Hel. v. p. 70. 



Zonites (Conula) samoensis, Mousson, Journ. de Conch. 1869, 

 p.331 ; 1870, p. 116; 1871, p. 10; Paetel, Cat. Conch. 1873, p. 86 ; 

 Schmeltz, Cat. Mus. Godeff. v. p. 90. 



Helix clayi, Liardet, Proc. Zool. Soc. 1876, p. 101, pi. 5. fig. 7. 



Microcystis samoensis, Garrett, Journ. Phil. Acad. Nat. Sci. 1881, 

 p. 384. 



This minute species is generally diffused throughout the group. 

 It is also common in the Tonga, Cook's, and Samoa Islands, and rare 

 in the Marquesas. Under decaying vegetation. 



It is a perforated, thin, depressed, turbinated, reddish or brownish 

 horn-coloured species, with five strongly convex whorls, the last one 

 angulated on the periphery. 



