276 



in character to 1. atkin^soni, Ire. and May, but is decidedly 

 less coars'e, and the umbo has a larger smooth area; the lateral 

 areas hardly show any of the radial sculpture of atkinsoni, 

 being fairly constantly ornamonted by much raised concentric 

 ribs, or undulations, the ordinary granulose sculpture between 

 the ribs. The ''coarse nodulose radials" of atkinsoni, as 

 described in the original description, are usually absent in this 

 sub-species. Ire. and May m.ention that the radials are 

 "dominated by the concentric growth -lines." Under a simple 

 lens the rugged character of the sculpture of the Tasmanian 

 shell is most consistent, whereas the mainland shell always 

 seems to havo a polished appearance, and the granulose 

 sculpture is less in evidence. 



The girdle scales are the same size as in atkinsoni, and 

 the ribbing on the scales is a little more finely cut; most 

 specimens of the latter show rougher and thicker scales, but 

 this difference is not absolutely constant. 



Ire. and May in the original description of 7. atkinsoni 

 (Proc. Mai. Soc, vol. xii,, pts. ii. and iii., 1916) state that 

 the colour is ''uniform buff," whereas Mr. May and I have 

 collected it in southern Tasmania more often of a dingy grey, 

 or greyish-white, with a huffish dorsal streak; others, again, 

 are- distinctly rufous. 



The sub-species now under consideration shows a much 

 greater range of variation. At San Kemo', in Victoria, from 

 which place I have a long series, a very wide range of vari- 

 ation exists. I quote from Ridgway's Colour Standards. 

 Many are drab (pi. xlvi.), similar to the southern Tasmanian 

 shells; others, again, are tawny-olive to verona-brown (pi. 

 xxix.). Two specimens are prussian-green (pi. xix.), with a 

 white dorsal band; another is dark grey with a white dorsal 

 band. From Cape Jervis, in South Australia, are specimens 

 varying from cream through pale-greenish shades to almost 

 black with cream girdle. Then at Marino the prussian-green 

 and a still more blue form occurs, also specimens ivory-white 

 to buff. Then at Port Lincoln they vary from pale greenish, 

 through grey shades and cream, orango-cinnamon. (pi. xxix.), 

 to chestnut. 



In nearly all there is a characteristic pattern which may 

 be described as a broad, central, lightish band with a crenu- 

 late darker band on each side; in a few cases this pattern 

 is reversed, the central band being dark and the edging light. 

 The girdle mostly shows banding. 



Hah. — 1 am indebted to Mr. James Kershaw for speci- 

 mens collected by himself at Wilson Promontory, Victoria, 

 which place probably forms the eastern extension of its range. 



