Helcioniscus.] GASTROPODA. 81 



Q 



are black dotted with white, especially in the young, this colourin_ 

 being less obvious on large shells. Apex at about the front third, 

 erect. Interior having alternating silvery and black rays, the latter 

 usually 11 in number ; the large central area black, suffused more or 

 less with cream colour in the depth of the apex. (Pilsbry.) 



Length, 32 mm. ; breadth, 25 mm ; height, 10 mm. 



Dentition. Button, T.N.Z.I., xv, 128, pi. 16, f. B (P. denticulata}. 



Type (?). 



Hab. Throughout New Zealand, but more common in the south. 



Remark. This species is very well characterized, and does not 

 show any very great variability, except that the apex is sometimes 

 quite anterior. 



Subsp. inconspicuus, Gray, 1843. Plate 7, fig. 12. 



Patella inconspicua, Gray, Dieff. N.Z.. ii, 244; Hutton, M.N.Z.M., 107; 

 P.L.S. N.S.W., ix, 373. Helcioniscu-s ornatus, Dillw., var. inconspicua 

 (Gray), Hutton, Man. Condi. (1), xiii, 138, pi. 68, f. 20-22; Suter, 

 P. Mai. 8., vi, 351. Patella luctuosa, Gould, P. Bost. S.N.H., ii, 150, 

 not of Hombr. & Jacq. 



Shell conical, high, the height often more than half the length. 

 Sculpture similar to that in the species, about 20 radiating ribs. Colour 

 light grey to dark brown, intermediate ribs without black and white 

 dots. Apex subcentral to the front third. Interior dark brown, with 

 1 1 white rays ; central area dark brown, much lighter under the 

 apex. 



Length, 32 mm. ; breadth, 25 mm. ; height, 17 mm. Length, 

 40 mm. ; breadth, 31 mm. ; height, 16 mm. Length, 24 mm. ; 

 breadth, 19 mm. ; height, 16 mm. 



Animal Hutton, T.N.Z.I., xiii, 203. 



Type in the British Museum. 



Hab. Throughout New Zealand. One of the common limpets. 



4. Helcioniscus radians, Gmelin, 1790. Plate 7, fig. 13. 



Patella radians, Gmel., Syst. Nat., ed xiii, 1790, 3720 P. argyropsis. Lesson, 

 Voy. Coq., 419. P. pholidota,liesson, I.e., 420. P. radiatilis, Hombron 

 and Jacquinot, Ann. Sci. Nat. (2), xvi, 191. P. sturnus, H. & J., I.e., 191. 

 P. fusca, L., Syst. Nat., ed. x, 784 (defined in an absurdly inadequate man- 

 ner). P. sagittata, Donovan: Rees, Encyclop. Conchol., xvi. P. floccata, 

 Reeve : Hutton, M.N.Z.M., 108, not of Reeve. Helcioniscus radians, 

 Gmel., Man. Conch. (1). xiii, 139, pi. 23, f. 4-8; pi. 09, f. 25-39: 

 Suter. P. M>xl. S., vi, 347. 



Shell ovate, depressed, thin but solid, slightly narrower in front. 

 Surface sculptured with decidedly separated narrow radiating riblets, 

 20 to 25, having a number of smaller riblets (sometimes obsolete) in 

 each interval, and decussated by fine crowded growth-striae, also 

 often obsolete, but usually cutting the surface just in front of the 



