534 POSITION OF PURPURA TRITON IFORMIS OF BLAINVILLE, 



After a careful study of the shell, its apex, the operculum, and 

 the mollusc itself, I have come to the conclusion that its right 

 place is in the genus Purpura, where it was first assigned. 



There are three varieties of the shell : firstly, the typical; 

 secondly, a stouter form confined to Lord Howe Island; thirdly, 

 a lighter form. 



The form selected as typical is of course that figured by Blain- 

 ville. Kiener's illustration seems a copy (too highly coloured) of 

 Blainville's. This aspect of the species is the commonest on the 

 coast of New South Wales; it also occurs at Lord Howe Island. 



P. TRiTONiFORMis, var. SMiTHi, Brazicr. 



Purpura Smithi, Braz., Aust. Mus. Mem. No. ii. Lord Howe 

 Island, p. 28, pi. ii., figs. 1-4, 7-12, 21, 22. 



Heavier, shorter and stouter than the type; spire shorter. 

 Sculpture: body whorl — spirals coarser than in the type, being 

 raised into stout cord-like ribs; longitudinals, consisting of coarse 

 hair lines, most prominent between the ribs, making the inter- 

 stices scabrous : spire — spiral ribs ornamented with nodules, as 

 broad as their interstices, in transverse oblique rows; the longi- 

 tudinal scabrous hair-lines gathered together between these 

 nodules to form riblets which tend to give the spire a latticed 

 appearance. Aperture smaller than in the type, the revolving 

 lirse within more prominent. Length 17-25, breadth 6-14 mm. 



This variety seems to be confined to Lord Howe Island. 



The name was given to it by Brazier in 1889, without a 

 description, and the figures of it then published were unfortu- 

 nately reversed in the press. 



P. TRITONIFORMIS, var. LEViDENSis, var.nov. 



Lighter than the type, but of the same outline. Sculpture — 

 spirals consisting of a multitude of fine lines overlying four or 

 five obsolescent broad low rounded ribs; longitudinals, eleven to 

 fifteen low rounded ribs slightly broader than their interstices 

 traverse the whorls, between which and the revolving ribs may 

 be seen the longitudinal scabrous hair-lines. Aperture rounder 



