SUTEK : NEW ZEALAND rOLYPLACOl'nORA. 



199 



lateral areas indistinctly raised. The margins of the lateral areas 

 and pleura show distinct granules (surrounded by numerous eye-dots). 

 The mucro seems to be central, but this is uncertain, since the surface 

 of the terminal valve has been scraped with a knife. Interior lead- 

 grey on posterior half of intermediate valves, white on anterior half 

 and tail valve. Central valves with 1-1, posterior valve with 9, 

 slits. Teeth rather long and very deeply pectinated outside in 

 a forward direction. Tegmentum inflexed at the posterior margin of 

 central valves. Teeth of end valve short, deeply pectinated on the 

 edge and outside. On central valves a well-defined ridge runs across 

 between the slits, following in outline the sinus and sutural lamiuoe. 

 Sinus deep, rounded, almost straight in the tail valve ; slightly notched 

 at the sides. Girdle (dry) dark-brown. In one place I found five 

 small calcareous spicules. The whole of the girdle is densely covered 

 by small pits, in which the lost spines were inserted, imparting to it 

 a somewhat spongy appearance. 



It is difficult to give an exact measurement of this shell, but 

 I estimate it at about : length 75, breadth 50 mm. 



The central valves are more broadly arclied than in Acanthopleura 

 gramdata, Gmel. 



Hah. — New Zealand, exact locality not known. 



ONITHOCHITON, Gray, 1847. 



29. Onithochiton ijndulatus (Quoy & Gaimard). 



Chiton imdiilatus, Quoy & Gaim. : Yoy. Astrolabe, Zool. vol. iii (1835), 



p. 393, t. Ixxv, figs. 19-24; Keeve, Conch. Icon., t. xvi, 



figs. 87, 90. 

 Onithochiton midulatus, Quoy & Gaim. : H. & A. Adams, Genera Rec. 



Moll., vol. i, p. 476, t. liv, fig. 3. 

 Tonicia undnlata, Quoy & Gaim. : Hutton, Trans. New Zealand 



Inst., vol. iv, p. 179 ; Man. New Zealand Moll., p. 114. 

 Onithochiton undalatus, Quoy & Gaim. : Pilsbry, Man. Conch., ser. 1, 



vol. xiv, p. 245, pi. Iv, figs. 14-16. 

 Tonicia lineolata, Frembly : Hutton, Man. New Zealand Moll., p. 114 



i^non Frembly). 



Mr. II. A. Pilsbry was quite right when ho expressed the opinion 

 (Man. Conch., ser. I, vol. xv, p. 89) that Tonicia lineolata reported 

 from Dunedin, Auckland Islands, and Campbell Island, was not likely 

 to be the Chilian form described in vol. xiv, p. 198. The specimens 

 from the localities mentioned are in the Otago Museum, and they show 

 the colour pattern of T. lineolata, but I found them all to be undoubted 

 0. undulatus. The colour variation in this species is greater than m 

 any other Chiton I know. Sometimes the colour is uniformly purjilish- 

 black, and this form is more common in the South, especially in the 

 Auckland Islands and Campbell Island. 



Hab.-kW the Southern New Zealand Islands. Often found in 

 roots of Durvillcca with Chiton Sinclairi and Plaxi^jliora ovata. 



