1879.] NATURAL SCIENCES OF PHILADELPHIA. 17 



LIST OF LAND SHELLS INHABITING RURUTU, ONE OF THE AUSTRAL 

 ISLANDS, WITH REMARKS ON THEIR SYNONYMY, GEOGRAPHICAL 

 RANGE, AND DESCRIPTIONS OF NEW SPECIES. 



BY ANDREW GARRETT. 



The small island of Rurutu = Oheatora of Capt. Cook, lies in 

 south lat. 22 34', and west Ion. 150 13', which is about 320 miles 

 S. S.W. from Tahiti. As near as I can ascertain it is about eight 

 miles in length, and has an elevation of about 1500 feet, over 100 



CT 7 



feet of which consists of ancient coral reefs, which" have been up- 

 heaved to that altitude. 



Mr. Hugh Cumins; was the first who visited the island for. the 

 purpose of collecting shells, and discovered two or three new spe- 

 cies. The next experienced collector, Mr. Charles De Gage, who 

 resides there, gathered a number of land shells, which he kindly 

 forwarded to me for identification, and which form the subject of 

 this paper. 



Microcystis subtilis, Anton. 



Helix subtilis, Anton, Verz. p. 35 ; Pfeiffer, Mon. Hel. vol. II. p. 33 ; 



Reeve, Conch. Icon. pi. Ill, tig. 626. 

 Helix vitrinella, Pfeiffer, Symb. vol. II. p. 41. 

 Helicopsis vitrinella, Beck, Ind. p. 20. 

 Nomina (Microcystis) subtilis, Albert, p. 60. 



Oheatora = Rurutu (Cuming). 



This species was not found by De Gage. 



Microcystis punctifera, sp. nov. 



Shell small, imperforate, orbicular, depressed, thin, smooth, 

 shining, transparent, light-brownish horn color, dotted with white; 

 spire convex ; suture linear; whorls 4|, depressly convex, radi- 

 ately striate beneath the suture, moderately and regularly increas- 

 ing; the last not descending in front, rounded on the periphery ; 

 base indented; aperture sub-vertical, orbicular lunate, wider than 

 deep ; peristome straight, simple, margins remote ; columella 

 slightly thickened with callus. 



Height 3, major diameter, 4j mill. 



It is smaller, and darker colored than subtilis, which latter is 

 pale horn color, and six mill, in diameter. It is more like M. brun- 

 nea collected by Cuming at Pitcairn's Island, which is about the 

 same color, with white dots, but like subtilis is six mill, in diameter. 



