MOLLUSCA. 81 



distances, eleven in the front one, and one on each side of the inter- 

 mediate valves. The interior is pale bluish, the latter valves having 

 an olive-brown stain radiating from the vertex behind on each side, 

 and the two terminal valves have marks of the same colour near the 

 middle. 



The girdle is covered with alternately pinkish and dark greyish 

 patches of fine oval compressed imbricating scales, of which those 

 towards the outer margin are much smaller than those near the 

 valves. 



Length without girdle 21 millim. ; diameter of fifth central plate 8. 



Hah. Port Jackson ( Coj5pireg'«r). 



This species is closely allied to O. antiquus, but is differently and 

 more finely sculptured and the scales on the mantle are larger. 



112. Chiton (Acanthopleura) spiniger. 



Chiton spiniger, Sowerhy, Conch. lU. fig. 68; Beeve, Conch. Icon. 



fig. 75; Gray, 1857, Ouide Moll. Brit. Mus. p. 184 (Maugeria)j; Ball, 



Bull. U.S. Nat. Mus. i. p. 80 (Acanthopleura). 

 Chiton granatus, Beeve, Conch. Icon. fig. ^4. 

 Chiton macgillivrayi, A. Adams, Proc. Zool. Soc. 1855, p. 120. 

 Acanthopleura glareosa, MS. in Mus. Cuming. 

 Maugeria owenii, Grai/, Guide Moll. p. 184. 

 P Chiton horbonicus, IJeshayes, Moll, de Beunion, p. 37, pi. v. figs. 



X^, J.O. 

 ? Chiton piceus, Beeve (non Gmetin), Conch. Icon. fig. 70. 

 = Chiton ohesus, Shvitleiaorth, Bern. Mittheil. 1853, p. 79. 

 ? Chiton cunninghamu, Beeve, I. c. fig. 18. 



Hah. Philippine Islands {Guming) ; Port Essington (Jukes) ; 

 Port Molle and Clairmont and Bird Islands (Coppinger); Kji, for 

 C. macgillivrayi. 



The specific diflference, if it exist, between the "West-Indian 

 G. piceus of Gmelin and G. spiniger is not very apparent. On close 

 comparison I find that the central valves of the former are as a rule 

 more peaked posteriorly, the colour within is bluish, with a con- 

 spicuous mark, almost black, at the jugal sinus. On separating 

 these valves the greatest diameter is found to exist at the posterior 

 margin, the laminae of insertion narrowing in front. On the con- 

 trary, in G. spiniger the greatest width is across the laminae anterior 

 to the lateral notch. There appears to be very little difference in 

 the insertion-teeth of the first and last valves of these two forms. 



113. Chiton (Acanthopleura) incanus. 



Chiton incanus, Gould, Proc. Bost. Soc. Nat. Hist. 1846, vol. ii, 

 p. 145; 'Otia,' pp. 6, 248 (Maugeria); Wilkes's Uxplor. Exped. 

 p. 315, figs. 432, 432 o. 



Hah. New South Wales {QouU); Port Jackson (Goppinger) ; 

 Stewart Island, New Zealand (C. Traill, Esq., in Brit. Mus.). 



Externally this species bears considerable resemblance to G. spi- 

 niger, both as regards the sculpture of the valves and the character 



