226 ACANTHOPLEURA. 



rupted into granules by wrinkles of increment ; lateral areas scarcely 

 denned. Divergence 127. 



The following is believed to be practically identical : 



C. piceus Reeve. (PI. 49, figs. 38, 39). Shell ovate, rather thick, 

 valves concentrically flatly ridged, interstices between the ridges 

 elevately striated and sometimes grained, umbos a little beaked ; 

 pitch-black, greenish on each side the umbonal summit ; ligament 

 horny, profusely beset with whitish short calcareous bristle-like pro- 

 cesses. New Holland, on the rocks (Cunningham). This I believe 

 to be the true C. piceus ; it is a thick ponderous shell, of which the 

 ligament, when in a good state of preservation, is covered with 

 calcareous bristle-like processes, as in C. spiniger but much finer. 

 (Reeve?) 



Chiton piceus REEVE, Conch. Icon., t. 13, f. 70, March, 1847. 

 ANGAS, P. Z. S. 1867, p. 223. TAPPARONE-CANEFRI, Zool. Viag. 

 Magenta, Malacologia, p. 77 (1874). C. obesus SHUTT., Bern. 

 Mittheil. 1853, pp. 67, 79. 



Angas says that this species is freely distributed on most parts of 

 the coast of New South Wales. The specimen commented upon by 

 Canefri was collected at Sydney ; but both may be founded ujftm 

 wrong identifications. Carpenter writes of the types as follows : 

 "Four specimens from Australia. The figure of Reeve is much 

 larger than the type, and would stand well for a perfect 

 cunning hami. The largest shell measures : length 77$, breadth 49 

 mill., divergence 108. This is a more raised shell than cunning- 

 hami, probably from its having grown in rougher water. Spines 

 very short, black, sometimes white. Sculpture almost entirely worn 

 away in all the specimens ; when seen it consists chiefly of concentric 

 wrinkles more or less broken into granules. The lateral areas are 

 scarcely distinguishable; mucro very perfect, post-median like 

 cunninghami, but rather more elevated, as is the rest of the shell." 



Subgenus MAUGERIA Gray, 1857. 



Maugeria GRAY, Guide Syst. Dist. Moll. Brit. Mus., p. 183 (in 

 part). Acanthopleura CARPENTER, Table Reg. Chit. 1873, and 

 Dall, Proc. U. S. Nat. Mus. 1881, p. 284, 289, 290 (in part); Not 

 Acanthopleura Guilding, q. v. 



Exterior lusterless; tail valve having numerous (7-12) slits in 

 the short crenulated insertion-plate, median valves 1-slit, the exposed 

 coating or tegmentum wider than the articulamentum or inner layer ; 



