170 MR. A. GARRETT ON THE TERRESTRIAL [Feb. 15, 



colour, and nodulous columella. It is more depressed and paler 

 than the preceding species. 



4. Microcystis excrescens. 



Nanina {Microcystis) excrescens, Mousson, Journ. de Conch. 1870, 

 p. 115, pi. 7. fig. i), 1871, p. 8 ; Paetel, Cat. Conch. 1873, p. 84; 

 Schmeltz, Cat. Mus. Godeff. v. p. 91. 



Helix excrescens, Pfeiffer, Mon. Hel. vii. p. 67. 



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

 p. 381. 



This small species was found by Dr. Griiffe on the eastern portion 

 of Viti Leva and on several islands in the Tonga group. I discovered 

 it on one of the Cook's Islands. 



It is nearly of the same size and shape as 31. nodulata, with the 

 columellar fold of M. Jcioaensis, but is much smaller than the latter 

 species. 



5. Microcystis upolensis. 



Nanina vpolensis, Mousson, Journ. de Conch. 18C5, p. 16G ; (Mi- 

 crocystis) 1809, p. 327; \870, \Rr. oneataensis, p. 114; {Thalassid) 

 Paetel, Cat. Conch. 1873, p. 85; Schmeltz, Cat. Mus. Godeff. v. p. 90. 



Helix upoletisis, Pfeiffer, Mon. Hel. v. p. 108. 



Helicopsis upolensis. Pease, Proc. Zool. Soc. 1871, p. 475. 



Helix samoensis, Baird, in Brenchlev, Cruise of the ' CuraQoa,' 

 p. 447, pi. xl. figs. 12, 13. 



This species was first described from specimens collected by Dr. 

 GrJiffe on Upolu, one of the Samoa Islands, and I subsequently dis- 

 covered it on the islands of Vanua Balavo and Oiieata. 



A very smooth, highly polished, orbicular, depressed, pale horn- 

 coloured species with a slight columellar nodule. 



6. Microcystis sororia. 



Helix sororia, Cox, Proc. Zool. Soc. 1870, p. 83 ; Pfeiffer, Mon. 

 Hel. vii. p. 60. 



This species, which is unknown to me, was discovered by Mr. Brazier 

 at Ovalau. 



A small imperforated, thin, smooth, shining species of the 

 depressed-globose form, with five moderately convex whorls, of a 

 uniform yellowish-olive colour, and with a simple columella. 



7. Microcystis firmostyla. 



Nanina firmostyla, Mousson, Journ. de Conch. 1865, p. 166; 

 (Microcystis) 1871, p. 7; Schmeltz, Cat. Mus. Godeff. v. p. 90; 

 (Microcystis) Paetel, Cat. Conch. 1873, p. 84. 



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



Helicopsis firmostyla, Pease, Proc. Zool. Soc. 1871, p. 475. 



Obtained by Dr. Giaffe at Tikombia, one of the Windward Islands. 

 He also found it generally distributed throughout the Tonga Islands. 



A minute, depressed-convex, highly polished, horn-coloured 

 species, shaped like M. upolensis, but only half as large. The colu- 

 mella is sometimes slightly nodulous. 



