18, A MONOGRAPH OP 



rounded, last somewhat depressed ; aperture roundly-lunate, peristome 

 simple ; margins approaching, joined by a thin callus ; columellar 

 margin faintly dilated. 



Diameter, gi-eatest 3 , least 2 ; height, IJ mil. 



Habitat. — Cataract, near Launceston. 



Obtained in considerable numbers on the rocks, gregarious under 

 masses of Jungermannia. It has a close relation to H. sitiens and £[, 

 Luchnani, but may be known from the first by the want of the regular, 

 prominent riblets ; and from the latte]' by its bronze-like general aspect, 

 and by not having the segments of colour generally present as in that 

 species. It is much larger, differently sculptured, and less globose than 

 H. Trucaninice. In habit they are all much the same. Hitherto I have 

 only collected it at the locality indicated, where it can always be got by 

 turning over the thick entangled masses of moss that form such a thick 

 carpet on the rocks a short distance above the water. It is very 

 probable that the present, with H. sitiens, H. LucTcmani, and H. 

 Trucanini, are but variations of one species ; the characters given are, 

 however, so constant that I prefer, for the present, to retain them as 

 distinct. 



24. — Helix ( ) sitiens — Cox, 



Legrand's Col. for Mon., sp. 60. 



Shell rather largely and openly umbilicated, depressed ; dusky- 

 brown, ornamented above and below with broad light-red rays ; trans- 

 versely striated with oblique, transverse, rather prominent riblets, at 

 regular intervals ; spire elevated ; whorls rounded, gradually increasing 

 in size, last whorl considerably depressed ; aperture sub-lunately 

 rounded ; peristome simple, bkmt ; margins closely approached ; 

 columellar margin straight, not dilated. 



Diameter, greatest 10, least 0*08 ; height, 0*05 of an inch. 



Habitat. — Near Hobart Town waterworks. Mount Nelson, Knock- 

 lofty, Queenborough (C. E. Beddome). 



On Knocklofty I have collected it in numbers, principally crawling 

 on the exposed surface of blocks of rock on the slopes of the hill, and 

 more sparingly under them, with H, Morti and H. Hobarti. To the last 

 it has a close resemblance, and principally differs from it by its larger 

 size, narrow umbilicus, sculpture generally, and by the rays of colour. 

 From H. Luckmani it may be known by the riblets and depression in 

 the last whorl. In habit they much resemble each other. 



