20 AMPHINEURA. [Polyplacophora. 



blue ; anterior valve with 8, central valves with 1 slit on each side ; 

 teeth sharp, lightly furrowed on the outer side ; tail valve with a strong 

 smooth and sinuated insertion plate ; sinus deep, convex ; sutural 

 laminae rounded, stout ; a strong valve-callus. 



My largest specimen is 45 mm. long by 22 mm. broad. An average 

 specimen : length, 25 mm. ; breadth, 11 mm. Divergence. 100-110. 



Type in the British Museum (Cuming collection). 



Hab. Coasts of the North and South Islands, more common in 

 the south ; Chatham Islands : under stones between tide-marks. 



Remarks. The ornamentation is very variable, and the ground- 

 colour varies from white to dark brown and black. The green-and- 

 pink colour-pattern mentioned by Reeve is very rarely met with ; 

 I found it only on specimens living in kelp-roots. 



4. Plaxiphora glauca, Quoy and Gaimard, 1835. Plate 3, fig. 13. 



Chiton glaucus, Q. & C4., Voy. Astrol.. iii, 376, pi. 74. f. 7-11. Plaxiphora 

 glauca, Q. & G.. Man. Conch. (1). xiv, 325. pi. 68. f. 68-72; J. Mai., 

 xii, 66. ? Plaxiphora ciliata, Angas, P.Z.S.. 1865. 187; not Chiton 

 ciliatus, Sowerby. 



Shell oval, widened at the sides, widely rounded, smooth ; greenish, 

 with black markings. Anterior valve with 8 low radiate riblets, inter- 

 stices smooth. Intermediate valves broadly rounded, with fine trans- 

 verse lines of growth on the central areas ; lateral areas not raised, 

 distinguished by a low rounded anterior rib ; sometimes 1 or 2 more 

 radiate, but always indistinct, ribs may be seen. Posterior valve 

 convex, with transverse lines, mucro terminal. Girdle of a beautiful 

 green (brown when dry), covered with rigid but not acute bristles of 

 the same colour. Colour brown, with longitudinal oblique and slightly 

 undulating bands of bluish-green ; along the back there is a triangle 

 of light brown, margined by bluish-green, on each of the central valves. 

 Interior emerald-green, anterior valve with 8 slits, intermediate valves 

 with 1 slit on each side, tail valve with a smooth insertion plate ; sinus 

 wide, spongy, sutural laminae broadly rounded, light blue. 



Length, 50 mm. ; breadth, 37 mm. 



Type. Mus. Hist. Nat., Paris. 



Hab. Chatham Islands (Fougere). The type is from d'Entre- 

 casteaux Channel. Tasmania. South Australia. 



Remarks. Specimens from the Chatham Islands are in my collec- 

 tion. It is rather curious that such a large shell should not have 

 been recorded before. 



5. Plaxiphora Murdoch!, Suter, 1905. Plate 3, fig. 16. 



Plaxiphora Murdoch!, Sut r, J. Mai., xii, 67, pi. 9. f. 11. 



Shell rather small, oval, slightly narrowed behind, roundly angled 

 along the top of the valves, blackish-green, finely sculptured, inter- 

 mediate valves mucronated ; girdle narrow, of a minutely scaly ap- 

 pearance, and with sparse hairlets. Anterior valve radiately 8-ribbed, 



