326 PKOCEEDINGS OF XHli MALACOLOGICAL SOCIETY. 



Acnma saccharma, L., var. perplexa, Pilsbry: Man. Concli. (1), vol. xiii, 



p. 50, pi. xxxvi, figs. 69-71. 

 Acmcm octoradiata, Hutt. : Hedley, Proc. Linn. See. N.S. Wales, 

 1904, p. 188; Hutton, Index Faun® Nov. Zeal., p. 1904. 



Shell depressed, star-shaped, whitish. There are 5 large rounded 

 ribs behind and 3 in front of the apex, reaching far beyond the 

 margin; they and their interspaces are all ornamented with fiue 

 radiate riblets. Colour white or creamy, with fine radiating reddish- 

 brown lines. Apex at about the anterior third, obtuse. Interior 

 white, with a few flesh-coloured spots ; border very narrow, dotted 

 with rufous ; spatula indistinct. Length 16, breadth 14, height 3 mm. 



Dentition unknown. Tj-pe in the Colonial Museum, Wellington. 



Hah. — West coast of the South Island (type); Eluif (A. Hamilton) ; 

 Chatham Islands. 



Although the dentition is unknown, there can be no doubt that this 

 species belongs to the subgenus CoUisellina. At the instigation of 

 Mr. Hedley the late Captain Hutton expressed the opinion that his 

 P. octoradiata and Pilsbry' s var. pcrplcxa are identical. 



Acmcea Chathanmisis, Pilsbry : Man. Conch. (1), vol. xiii, 1891, p. 56, 

 pi. XXXV, figs. 43-46. 

 A specimen in my collection fiilly agrees with the diagnosis and the 

 figures given by Pilsbry, except the apex being more anterior, the 

 interior distinctly iridescent, with a silvery lustre, and the spatula cream- 

 colour. The dimensions are almost exactly those given by Pilsbry for 

 the larger specimen. I have not the least hesitation in assigning this 

 species to Helcioniscus radians, Gmel., subsp. affinis, Ileeve, of which it 

 represents an extreme form. (The dimensions given for ITelc. affinis in 

 these Proceedings, vol. vi, p. 349, sliould read : 33 x 27 x 7 mm.) 



EXPLANATION OF PLATE XXVII. 



