SDTEK : ACM^IDJi; OF NEW ZEALAND. 325 



Shell solid, depressed, irregularly oval, strongly ribbed, whitish, 

 margin laciniate. The sculpture consists of 7 radiating angular ribs, 

 rounded above, thick, separated by wide depressions, three in front, 

 four behind the apex ; in the interspaces between these main ribs there 

 are one or two smaller ribs ; all of these ribs strongly and irregidarly 

 denticulate the margin. Strong concentric ridges are mostly present. 

 Colour dirty white or greenish, with black in double interrupted 

 circles. Apex situate at the anterior third. Inside bluish - white, 

 spatula light brown or blue, dotted with brown ; the margin with 

 a few dark-brown spots or a continuous brown border, tips of rays 

 white. 



Length 21, breadth 19, height 6-2,5 mm. Type. 



,, 21, ,, 18, ,, 5 ,, Specimen figured. 



Dentition : Fig. 37 shows the central and lateral teeth typical, and 

 two marginals on each side in addition. 



Hab. — Heads of Wellington Harbour and Island Bay, Cook Strait 

 (Miss M. Mestayer) ; Taumaki Island, west coast of South Island, in 

 10 fathoms (Captain Bollons). 



This species is very closely allied to A. alticostata, Angas, from 

 Australia and Tasmania. 



ACM^A STELLA (LeSS.), SUbsp. CORTICATA, HuttoU. PI. XXVII, 



Figs. 38-41. 

 Acmcea corticata, Hutton : Man. N. Zeal. Moll., 1880, p. 89; Proc. 



Linn. Soc. N.S. Wales, vol. ix, p. 372. 

 A. lacunosa, Reeve: Hutton, Trans. N. Zeal. Inst., vol. xvi, p. 215; 

 Pilsbry, Man. Conch. (1), vol. xiii, p. 52, pi. xxxvii, figs. 7-11, 

 not of Eeeve. 

 Shell oval, conoidal, ribbed. There are 14 to 22 rounded, roughened, 

 radiate ribs, a few of them short, crossed by incremental ridges. Colour 

 white, nearly always obscured by a layer of Nulliporites. Apex a little 

 in front of the middle, obtuse; slopes straight; margin denticulate. 

 Inside bluish-white, spatula white or brown, sometimes faintly radiately 

 streaked with black ; margin with a black border or dark-brown spots. 

 Length 14, breadth 13, height 9 mm. Type. 



„ 13, ,, 9-5, ,, 5 „ Specimen figured. 

 Dentition: Hutton, Trans. N. Zeal. Inst., vol. xv, p. 127, pi. xv, 

 fig. L. A copy of Hutton's figure is here reproduced (Fig. 41). Type 

 in the Canterbury Museum, Christchurch. 



Rab. — The type is from Dunedin ; North and South Islands and at 

 the Chatham Islands. 



This subspecies is distinguished from the species by the usually 

 smaller size and the disappearance of the seven primary stronger ribs. 

 The margin is not laciniate, and the ribs are more numerous and equal. 



15. ACM^A OCTORADIATA (Huttou). 



Patella octoradiata, Hutton: Cat. Mar. Moll. N. Zeal., 1873, p. 44. 

 P. stellaris, Q,. & (i. : Hutton, Journ. de Conch., vol. xxvi, p. 37, non 

 Quoy & Gaimard. 



VOL. YII. — SEPTEMBER, 1907. '^'^ 



