Acmcea.\ GASTROPODA. (57 



blue, occasionally light brown, central area chestnut-brown ; the 

 sharp margin having a rather broad brown border, often banded 

 or dotted with yellowish-brown. 



Length, 17 mm. ; breadth, 13-5 mm. ; height, 4-5 mm. 



Dentition. Suter, P. Mai. S., vii, pi. 27, f. 17, 18. 



Type in the British Museum. 



Hob. The type was collected in New Zealand by Earl, no exact 

 locality given ; Oamaru ; St. Clair, Dunedin (H. S.) ; Grey mouth ; 

 Preservation Inlet ; Auckland Islands; Macquarie Island (A. Hamilton). 



Remarks. At first sight this species seems to be a young A. pileopsis, 

 but there are some points which separate the two. First of all, 

 A. cantharus never attains a much larger size than that indicated ; to 

 the naked eye it is smooth, the radial sculpture being visible only 

 under a good lens. If exceptionally a few ribs are present, they are 

 much farther apart than those of A. pileopsis. The apex is much 

 sharpe and more hooked, also much more constant in its anterior 

 position. The inside between marginal band and central area is really 

 light blue, not whitish or bluish-white as in A. pileopsis. It lives, 

 like most other species, on rocks between tide-marks ; and I have 

 never seen it high up, where only the spray of the sea could reach it. 



7. Acmaea dsedala, Suter, 1907. Plate 5, fig. 11. 



Acmaa dasdala, Suter, P. Mai. S., vii, 323, pi. 27, f. 30-32. A. flammea, Quoy 

 and Gaimard: Hutton, T.N.Z.I., xv, 1882 (1883), 132; P.L.S. N.S.W., 

 ix, 373, not of Quoy and Gaimard. A. dcedala, Sut., T.N.Z.I.. xl, 379. 



Shell small, oval, depressed, pellucid, radially netted with brown, 

 apex anterior. The sculpture consists of numerous microscopic radiate 

 striae, crenulated by fine incremental lines. Colour light yellow ; 

 numerous light-brown radiate lines give, by anastomosing the whole 

 surface a net-like appearance. Apex anterior, at about the anterior 

 eighth, slightly pointed ; anterior slope concave. Interior bluish- 

 yellow, showing the ornamentation of the outside ; central area in- 

 distinctly marked ; margin sharp. 



Length, 7 mm. ; breadth, 5-5 mm. ; height, 2 mm. (type). 



Dentition, Hutton, T.N.Z.I., xv, 128, pi. 15, fig. N; P. Mai. S., 

 vii, pi. 27, f. 32. 



Type in the Canterbury Museum, Christchurch. 



Hob. Auckland Harbour (type) ; Rakino Island ; Cook Strait ; 

 Wellington Harbour ; Sumner ; Lyttelton ; Greymouth ; according 

 to Hutton, it is found as far south as Dunedin ; Shag Point ; Cape 

 Saunders (Iredale). 



Remarks. In this instance again the late Captain Hutton cannot 

 have seen specimens of A. flammea, Q. & G., or he would never have 

 assigned our small, fragile, and pellucid shell to that species, which 

 is much larger and solid. This is one of our fairly constant species. 



Fossil in the Pliocene. 



3* 



