178 CHITON. 



C. JUGOSUS Gould. PL 36, figs. 91, 92, 93, 94, 95. 



Shell oblong, much elevated, carinated, the side-slopes straight 

 and steep. Central areas sulcate at the sides, smooth in the middle, 

 lateral areas smooth. Color light green, the ribs of the central areas 

 orange, lateral areas with fine alternating concentric lines of yellow 

 and green. 



The lateral areas are strongly raised and smooth, painted with 

 close lines parallel to the dorsal keel. Central areas having a smooth 

 triangle in the middle, the sides sculptured with 11-14 strong 

 rounded orange colored ribs, separated by deep, blue intervals of 

 the same width. Head valve smooth, concentrically lineated ; tail 

 valve concentrically lined at the sides, having a broad triangular 

 buff or orange ray behind, extending, across the girdle ; apex project- 

 ing slightly behind the middle, posterior slope strongly concave. 



Interior blue-white, the sutural plates white. Sinus narrow and 

 angular, denticulate. Anterior valve having 8, central valves 1, 

 posterior valve 12 slits; teeth blunt, pectinated. Eaves spongy. 



Girdle (fig. 95) buff and greenish, irregularly alternating, covered 

 with compactly imbricating, polished convex scales, which are obso- 

 letely striated. Length 35, breadth 20 mill. 



Port Jackson, Sydney, N. S. Wales, Australia. 



Chiton jugosus GOULD, Proc. Bost. Soc. N. H. ii, p. 142 (1846) ; 

 Expl. Exped. xii, Moll. & Sh., p. 317, atlas, t. 28, f. 430 (1852). 

 SMITH, Zool. Coll. H. M. S. ' Alert,' p. 78 (1884). HADDON, Chall. 

 Polyplac., p. 22 (1886). Lophyrus jugosus GLD., Otia, p. 3, 242 

 (1862). ANGAS, P. Z. S. Lond. 1867,. p. 222. Chiton concentricus 

 KEEVE, Conch. Icon., t. 16, f. 95 (1847). Lophyrus concentricus 

 ANGAS, P. Z. S. 1867, p. 221. 



The peculiar and beautiful coloration separates this species from 

 its allies. The second valve is frequently blood red, or blotched at 

 the sides with dark sepia ; and occasionally all or many of the valves 

 have blotches of buff interrupting the longitudinal color-lines. The 

 light triangle radiating backward from the umbo of the tail valve is 

 present in every specimen I have seen. The tail valve, indeed, 

 reminds one somewhat of that of an irregular Chiton. 



The painting of the lateral areas gives the impression that they 

 are longitudinally ribbed, as Keeve and Angas have described ; but 

 even in Reeve's types these areas are quite smooth, as they are in all 

 the specimens I have seen. 



