84 GASTROPODA. [AspidobrancMa. 



Type in the British Museum. 



Hab. Ngunguru Harbour ; Stonyhurst ; Te Onepoto ; Preser- 

 vation Inlet ; Chatham Islands ; Disappointment Island, Auckland 

 Group (Captain Bollons). 



Remarks. An exceedingly variable subspecies, but always more 

 elongated than the species. Pilsbry's Acmcea chathamensis is one of 

 the extreme forms of the subspecies. 



Subsp. flavus, Button, 1873. Plate 7, fig. 18. 



Patella flava, Hutt., C.M.M., 44. Patinella flava, Button. P.L.S. N.S.W., ix, 

 378. Hdcioniscus flavus, Hutt., Man. Conch. (1), xiii, 142. H. radians, 

 Gmel., subsp. flava, Hutt. : Suter, P. Mai. S., 349. 



This subspecies is best described as a conical, pale-yellow form of 

 decor us, Phil. The apex is subcentral, sometimes nearly reaching the 

 anterior third of the length. Small shells are, as a rule, depressed, 

 but adult specimens have mostly a high conical form. The distant 

 broadly rounded ribs number 20 to 22, and are almost always of the 

 same colour as the shell ; specimens from Stonyhurst have sometimes 

 one or several ribs dark brown. Interior light to orange-yellow, iri- 

 descent, central area light orange to cream colour. 



Length, 55 mm. ; breadth, 46 mm. ; height, 26 mm. (specimen 

 from Kaikoura). Length, 50 mm. ; breadth, 42 mm. ; height, 22 mm. 

 (specimen from Stonyhurst). Length, 45 mm. ; breadth, 37 mm. ; 

 height, 18 mm. (specimen from Napier). 



Type in the Dominion Museum, Wellington. 



Hab. South Island : Stonyhurst; Amuri Bluff (type) ; Motanau 

 Island ; Kaikoura. North Island : Napier ; Gisborne ; East Cape. 

 Chatham Islands. 



Subsp. olivaceus, Button, 1882. Plate 7, fig. 19. 



Patella olivacea, Hutt., N.Z.J.S., i, 1882, 69. Patinella radians, Gmel., 

 var. olivacea, Hutton, P.L.S. N.S.W., ix, 377. Helcioniscus olivaceus, 

 Hutt., Man. Conch. (1), xiii, 141, pi. 70, f. 46-48. H. radians, Gmel., 

 subsp. olivacea, Hutt. : Suter, P. Mai. S., vi, 349. 



This subspecies is very much like the large conical form of argenteus, 

 Q. & G., but distinguished from it chiefly by the very numerous 

 (about 70) fine and uniform radiate riblets, the olive colour of the 

 shell, and the black margin on the inner edge, which, however, is not 

 a constant character. 



Length, 33 mm. ; breadth, 28 mm. ; height, 14 mm. 



Dentition. Button, T.N.Z.I., xv, 128, pi. 16, f. D. 



Type in the Canterbury Museum, Christchurch. 



Hab. From Sumner, near Lyttelton, along the east coast to 

 Preservation Inlet, South Island. Rather rare, but always together 

 with argenteus, Q. & G. 



