Acmcea.] GASTROPODA. 73 



The dentition is very similar to that of A. fragilis, Suter. P. Mai. S., 

 vii, pi. 27, f. 12- H. 



Type, in the Mus. Hist. Nat., Paris. 



Hob. Chicken Island (C. Cooper) ; west coast of Manukau (C. 

 Spencer) ; Heathcote Estuary (Iredale) ; Dunedin ; Auckland Islands 

 (Captains Hutton and Bollons) ; Campbell Island (Captain Bollons). 

 On rocks between tide-marks. Found also in Australia and Tasmania. 

 The type is from King George's Port, Western Australia. 



Remark. The variability of this species is very remarkable ; the 

 sculpture, the colour, and the shape differ to such an extent that it 

 is no wonder it has received several specific names. 



Subgen. 2. COLLISELLINA, Dall, 1871. 



Collisellina, Dall, Amer. Jouvn. Couch., vi, 1871, 154. Type : A. saccha- 

 rina, L. 



Muzzle without lappets ; marginal teeth present, 2 on each side. 

 Formula of teeth : 2 .2 (1 + 0+ 1) 2 .2. 



14. Acmaea stella, Lesson, 1830. Plate 5, fig. 16. 



Patella stella, Lesson. Voy. Coq., Zool., ii. 1830, 421. Acmcea stella, Suter, 

 P. Mai. S., vii, 1907, 324, pi. 27, f. 36, 37. 



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, 3 in front, 4 be- 

 hind the apex ; in the interspaces between these main ribs there are 

 1 or 2 smaller ribs ; all of these ribs strongly and irregularly denticu- 

 late 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 ; central area 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 mm. ; breadth, 19 mm. ; height, 6-25 mm. (type). 

 Length, 21 mm. ; breadth, 18 mm. ; height, 5 mm. (specimen figured). 



The dentition (Plate 1, fig. 1) consists of short, broad, rounded 

 median and lateral teeth, and on each side posteriorly 2 elongated 

 denticulate marginals. 



Type (?) 



Hob. Heads of Wellington Harbour and Island Bay, Cook Strait 

 (Miss Mestayer) ; Taumaki Island, in 10 fathoms (Captain Bollons) ; 

 East Cape. 



Remark. This species is very closely allied to A. costata, Sow., 

 of Australia and Tasmania. 



