JOURNAL OF CONCHOLOGY. 287 



DESCRIPTION OF HELIX PETTERDIANA, 

 NEW SPECIES. 



By JOHN W. TAYLOR. 



Shell with an open umbilicus, in which the whorls are freely 

 exposed, broadly-discoidal; yellowish, occasionally white, marked 

 very irregularly with dashes and waved streaks of reddish-chestnut, 

 marking often quite absent; spire very faintly elevated, finely, 

 rather closely striated with waved liblets above and below, inters- 

 tices under the lens discussate, extending over the riblets ; whorls 

 j\\, prominently rounded, last scarcely descending in front ; 

 peristome acute ; aperture almost round ; margins closely ap- 

 proaching, not dilated. 



Diameter, greatest 6, least 5; height, 2| mil. 



Variety albida. — White, without markings. 



Habitat — Circular Head, Table Cape, Emu Bay, Torquay, 

 Launceston, Mount WelUngton, islands in Bass 

 Straits, and Fernshaw (Victoria). 



A very pretty species, having a close resemblance to H. 

 MacDonaldi and a remote one to H. Tasmanice. and H. Tamar- 

 eiisis. To the former it is so closely allied that it may be but a 

 large variety; from the two latter it may be dii>tinguished by 

 attending to the diagnosis. At Circular Head it is in great 

 abundance on the rocks around the "Nut," gregarious under 

 entangled masses of plants in company with H. coesus, H. Weldii, 

 and H. pictilis. So plentiful is it that thousands can be literally 

 scraped together from the surface of a single block of rock, on 

 lifting the accumulated mass of plants and leaves. No other 

 species are found in such great numbers as the present and 

 its companion H. aesiis. There is a New Zealand shell having 

 some resemblance to it, but quite specifically distinct. The 

 nearest Australian species is H. Miirraya7ia, but that differs in 

 several respects. 



