CHITONID&. bin Oy 
feather ; the posterior terminal valve has the mucro quite terminal; the 
anterior valve radiately eight-ribbed with diverging oblique striations on 
each side of them; interior greenish-blue; valve lobes whitish, the 
sinus between them deep ; bristles on the mantle short, few, and horny, 
those from the nine pores being thicker than the rest (Smith.) * 
Length, 1°65; breadth, °8 inch or less. 
Genus, ACANTHOCHITES—Risso. 
Mantle densely spinulose, surrounded with a series of setigerous 
pores. Shell with the valves deeply immersed, sub-equal, externally 
contiguous, the exposed part moderate, cordate, as broad as long ; plate of 
insertion of the anterior valve six-lobed, that of the middle bi-lobed, that of 
the posterior five-lobed. 
A. zealandicus, Quoy and Gaimard, Voy. Astrolabe, i1., p. 400, pl: 
73,J. 5-8; A. hookert, Gray, Dieff. N.Z., ii., p. 262; Reeve, Conch. ILc., f. 58. 
Oblong; mantlespiny, with nine large radiating tufts of spineson each side; 
valves flatly triangular, sub-carinate ; posterior margins slightly convex, 
with an obtuse central point; terminal and lateral areas granulose ; 
median areas smooth ; lateral areas very large; mantle brown; spines 
pale green; valves generally greyish-black, more or less varied with 
yellowish ; often yellowish or reddish on the dorsal line; occasionally 
greenish. 
Length, 1; breadth, °4. 
Auckland to Dunedin. Japan. 
Not uncommon on stones below low watermark. 
The spines on the mantle vary from green to brown. Green is the 
more common colour in thé north, while brown appears to be universal 
in Otago. 
A. porphyreticus, Reeve, Conch. Ic., f 56. Shell somewhat 
elongately ovate ; valves punctured in the middle, verrucosely rough on 
each side, with a single ridge along the edge of the lateral areas ; 
anterior terminal valve radiately five-rribbed ; posterior small, blunt ; 
cinerous purple, with a conspicuous yellow spot, dotted with black at 
the edge, and stained with bright purple in the middle, along the 
umbonal summit of each valve (Reeve.) 
Dunedin. Cook Strait. 
A. ovatus, Hutton, Trans. N.Z. Inst., iw., p. 182. Ovate, 
attenuated in front; margin spiny, with nine small bundles along each 
side; valves flatly triangular, sub-carinate ; posterior valve very narrow ; 
apex recurved ; posterior margins of the anterior plate sloping back- 
wards into a point, those of the posterior plates nearly straight} anterior 
valve with ten, and lateral areas with two on each side, radiating nodu- 
lose ridges; median areas with slightly waved longitudinal ridges ; 
dorsal line smooth ; mantle pale reddish-brown ; spinés white ; valves 
greenish-white ; yellowish on the dorsal line. 
Length, °6; breadth, ‘5. 
Cook Strait. Dunedin. On seaweed. 
