324 PROCEEDINGS OF THE MALA.COLOGICAL SOCIETY. 



AcM^A D^DALA, Sutei", subsp. sTTBTiLis, n.subsp. PI. XXVII, 

 Fig. 33. 

 This subspecies has the same microscopic sculpture as the species, 

 but it is more transparent, more fragile, smaller, whitish, ornamented 

 with fine, radiate, and narrow brown lines. Interior whitish, showing 

 all the brown lines; spatula slightly greenish, polished, but indistinctly- 

 circumscribed. 



Length 2'5, breadth 1"5, height 0-05 mm. Type. 



,, 6'5, ,, 4'5, ,, 1*75 ,, Taumaki specimen. 

 Dentition unknown. Type in my collection. 



Hah. — Between Little Barrier Island and Tiri - Tiri Island in 

 20 fathoms, type (R. H. Shakespear) ; Taumaki Island, in 10 fathoms 

 (Captain Bollons). 



12. AcM^A Helmsi, E. a. Smith. 

 Acmcea Hchnsi, E. A. Smith: Proc. Malac. Soc, vol. i, 1894, p. 58, 

 pi. vii, figs. 4-5 ; Hutton, Index Faunae Nov. Zeal., p. 85. 



Shell small, depressed, cap - shaped, almost smooth, bluish - grey, 

 ornamented with numerous radiating, reddish - black narrow lines; 

 apex subterminal, anterior slope .slightly concave, posterior slope 

 convex, arcuate. Interior greenish, central area white, with a few 

 rufous spots, margin but faintly crenulate ; border narrow, yellow, 

 marked all round with reddish - black rays (E. A. Smith). Length 

 11-5, breadth 9, height 4 mm. 



Dentition unknown. Type in the British Museum. 



Hah. — Greymouth, type (R. Helms) ; Cape Egmont (R. Murdoch). 



13. AcM^A scAPHA, n.sp. PL XXVII, Figs. 34-35. 



Shell very small, long and narrow, laterally compressed, sides 

 parallel. Nearly the whole surface of my specimens is eroded, but 

 near the margin traces of radiate fine riblets can be seen. Colour 

 light brown, with a few concentric bands of darker. Apex situated 

 at about the anterior fourth, rounded ; side-slopes steep and straight, 

 anterior slope straight, posterior slope convex. Inside with the spatula 

 dark brown, lighter under the apex, a narrow brown border on the 

 margin, space between this and the spatula covered by a whitish 

 callus. Length 4, breadth r75, height TS mm. 



Dentition unknown. Type in my collection. 



Hah. — Dunedin (A. Hamilton). 



This curiously shaped species resembles somewhat the Californian 

 species A. paleacea, Gould, and A. depicta, Hinds. Whether in this 

 case the narrow elongated form is an adaptation to an existence on 

 fronds of seaweeds I am unable to say, but it seems very likely. 



Subgenus Collisellina, Dall, 1871. 

 Formula of teeth of radula, 2.2 (1+0 + 1) 2.2. Type, 

 A. saecharina, L. 



14. AcM^A STELLA (Lessou). PI. XXVII, Figs. 36-37. 

 Patella stella, Lesson: Voy. Coquille, Zool., vol. ii, 1830, p. 421; 

 Hutton, Man. N. Zeal. Moll., 1880, p. 110. 



