Aemcea.] GASTROPODA. 75 



Animal unknown. 



Type in the Canterbury Museum, Christchurch. 

 Hab. Lyttelton Harbour (type) ; Taylor's Mistake. Bay ; Shag 

 Point, Otago ; Otago Peninsula. On rocks, almost at high-tide mark. 

 I have not seen this shell. 



15. Acmaea octoradiata, Hutton, 1873. Plate 7, fig. 6. 



Patella octoradiata, Hutton, C.M.M., 44. P. stellaris, Q. & G. : Hutton, 

 J. de Conch., xxvi, 37, non Quoy and Gaimard. Acmtea saccharina, 

 L., var. perplexa, Pilsbry, Man. Conch. (1), xiii, 50, pi. 36, f. 69-71. 

 A. octoradiata, Hutton : Heclley, P.L.S. N.S.W., 1904, 188 ; Suter, 

 P. Mai. S., vii, 325 ; Verco, T.R.S. S.Aust., xxx, 209. 



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 fine 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 ; central 

 area indistinct. 



Length, 16 mm. ; breadth, 14 mm. ; height, 3 mm. 



Dentition unknown. 



Type in the Dominion Museum, Wellington. 



Hab. West coast of the South Island (type) ; Bluff (A. Hamilton) ; 

 Chatham Islands. Also Tasmania and Australia. 



Remark. There can be but little doubt that this species belongs 

 to Collisellina. 



Fam. PATELLID^I. Guilding. 



Docoglossate Gastropods breathing by a cordon of branchial 

 leaflets attached to the mantle between its thickened edge and the 

 sides of the foot ; having no cervical gill-plume. Radula with 3 

 marginal and 3 lateral teeth on each side, the central tooth being 

 either present, rudimentary, or wanting ; jaw developed. They feed 

 on algae, and live mostly on rocks. 



Shell conical, non-spiral even in the embryo. 



The Patellidce differ from the Acmceidce in the gills, which form 

 a complete or interrupted cordon, not accompanied by a cervical 

 branchial plume, and not homologous with the gills developed in 

 other Streptoneura. 



The shells may generally be distinguished from those of the 

 Acmceidce by their texture and the lack of a defined internal border. 

 The apex is, as in the Acmceidce, subcentral or marginal, but always 

 nearer the anterior margin ; the central area and the muscle-scar are 

 also similar in the two families. 



Limpets. 



This family dates back to the Ordovician, but is still found in the 

 littoral zone of most seas. 



