92 ISCHNOCHITON. 



oblique zigzag rows ; but toward the sides of the central areas, 

 along the diagonal slope, a coarse sculpture of longitudinal wrinkles 

 is developed. End valves sculptured like the lateral areas; umbo 

 of posterior valve rather obtuse, the posterior slope concave. 



Interior white and blue or blue-green; posterior valve having a 

 black crescent. Anterior valve having 10, central valves 1, poste- 

 rior valve 9 slits. Teeth sharp, thin, smooth outside, but slightly 

 roughened inside ; posterior tooth of the side plates terminating 

 abruptly near the posterior edge of the valve. Eaves narrow, solid. 



Girdle indistinctly marbled with ashy-purple on a paler ground ; 

 very closely covered with microscopic, deeply imbricating striated 

 scales (fig. 79). Length 33, breadth 15 mill. 



New South Wales. 



Chiton ftuticosus GOULD, Proc. Bost. Soc. Nat. Hist, ii, p. 142 

 (July, 1846) ; U. S. Expl. Exped. p. 319, f. 428 ; Otia, p. 4, 242. 

 Ischnochiton fruticosus CARPENTER, MS. and of HADDON ? Chal- 

 lenger Polyplac. p. 17. Isch. sowerbyi n. s. ?, CPR., MS. 



This species has the lateral areas more roughly and irregularly 

 sculptured than /. longicymba or /. haddoni, and the girdle is some- 

 what more compactly, flatly scaled than either. The external 

 sculpture of the valves is extremely similar to /. divergens Rve. ; 

 but the latter differs totally in its very coarsely pebble-scaled girdle. 



I. SCULPTUS Sowerby. PL 23, figs. 89, 90. 



Shell subelongate, depressed, subattenuated in front, back 

 rounded. Central areas smooth, striated at the sides ; lateral areas 

 ornamented with radiating exfoliating ribs ; margin smooth. 

 Length 20, breadth 10 mill. (Sowb.) 



Habitat unknown. 



C. sculptus SOWERBY, Mag. of Nat. Hist, iv, p. 292, June, 1840 ; 

 < "nch. Illustr. No. 44, f. 66. REEVE, Conch. Icon. no. 177, t. 26, 

 f. 121. 



A beautiful little shell, remarkable for the exfoliated sculpture of 

 the lateral areas, on each side of which there are three radiating 

 series of strongly relieved laminae. The central areas are nearly 

 smooth except at the sides, where they are slightly striated. The 



niaririn i- nearly sm<>oth, li.trlit brown invirularly striped with gray ; 

 and the general color is creamy-white. (Soivb.) 



