MoUusca.] SUBANTARCTIC ISLANDS OP NEW ZEALAND. 



dashes on the sides. Girdle wide, black, with sutural tufts of very long bristles. 

 Anterior valve short and broad, flattish, with 8 granulated radial ribs. Intermediate 

 valves wide, depressed, the jugum smooth, with very fine growth-lines ; lateral 

 areas not raised, with 2 narrow granulated ribs, the interspaces smooth. Posterior 

 valve smooth, small, the mucro posterior, the hind slope nearly straight. Girdle 

 broad, with very prominent sutural tufts round the anterior and a few round the 

 posterior valve ; a second series of tufts with shorter bristles near the margin, which 

 is beset with short brownish hairs ; remainder of the girdle quite naked, smooth. 

 Colour of the valves light brown ; intermediate and tail valves usually with a dorsal 

 triangular white area with a longitudinal brown median line ; one or two white elon- 

 gated spots are mostly present on the pleural, rarely on the lateral areas ; girdle black. 



Length, about 15 mm. Divergence, 105°. 



The specimen could not be disarticulated without completely destroying the 

 valves. 



Type in the Canterbury Museum, Christchurch. 



Hob. — Musgrave Harbour, Auckland Islands (Edgar R. Waite). 



Plaxiphora superba, Pilsbry, 1893. 



Plaxifhora superba, Pilsbry, Man. Conch. (1), xiv, 1893, p. 319, pi. Ixviii, figs. 55-61. 

 Plaxiphora subatrata, Suter, P. Mai. S., ii, 1897, p. 190, figs. 7-11 in text. 



Shell attaining a large size ; the posterior valve not much reduced in size or 

 altered in form ; central areas unsculptured save for growth-lines ; sutural pores 

 or tufts distinctly developed ; lateral areas with 2 to 4 low flat ribs. Colour reddish- 

 olive, maculated with darker and paler, or reddish-brown, the jugum dirty pink 

 or with a wedge-shaped white stripe with a brown one in the centre. The shape 

 of the intermediate valves is subject to great variation, from narrow and high to 

 wide and low, but all intermediate grades occur. 



Length, 60-75 mm. ; breadth, 40-45 mm. Divergence, 110°-125°. 



if oi.— Auckland Islands (Professor Benham) ; Campbell Island (Professor 

 Chilton). 



Also Macquarie Island (A. Hamilton). 



This species may be P. camphdli, Filhol (Compt. Rend., xci, 1880, p. 1095), 

 which was insufficiently described, and not figured. 



Fam. ACANTHOCHITIDAE, Pilsbry. 

 Genus Acanthochites, Risso, 1826. 

 DistribtUion. — -World-wide. 



Acanthochites (Loboplax) rubiginosus (Hutton), 1872. 

 Tonieia rubiginosa, Hutton, T.N.Z.I., iv, 1871 (1872), p. 180. Acanthochites costatus, 

 Ad. and Ang. : Suter, P. Mai. S.. ii, p. 194 (not of Adams and Angas). 

 Acanthochites rubiginosus, Hutton : Suter, Journ. Malac, xii, p. 68, pi. ix, 

 figs. 12-17. 

 ^a6.— Auckland Islands (Captain J. Bollons). 

 In the laminarian zone, from Hauraki Gulf to the Bluff. 



