CHITON-RADSIA. 191 



one side, 2 on the other), posterior valve 18-19 slits. Teeth blunt, 

 pectinated; eaves narrow, spongy. 



Girdle covered with shining, convex, minutely striated scales. 



Coquimbo, Chili. 



Chiton barnesii GRAY, Spicil. Zool., p. 5, t. 6, f. 22. SOWB. in 

 Moll. Beechey's Voy., p. 149, t. 41, f. 10; Conchol. Illustr., f. 2. 

 KEEVE, Conch. Icon., t. 1, f. 1 ; t. 21, f. 137. 



Entirely different from the other species of Radsia in form and 

 sculpture. The riblets upon the central areas are very fine and 

 their interspaces shallow. Occasionally a specimen occurs having 

 some of the valves with a single slit one side. 



C. GOODALLII Broderip. PI. 29, fig. 9 ; pi. 28, figs. 5-8. 



Shell very large, oval, moderately elevated, carinated, the side- 

 slopes nearly straight or rather convex. Surface nearly smooth. 

 Color blackish, olive-black or brown-black, generally showing an 

 obscure olive-green stripe on each side of the keel. 



The lateral areas are a little raised, separated by an obtuse ridge 

 from the central areas, and in most specimens they are somewhat 

 terraced by concentric marks of growth-arrest. There is no other sculpt' 

 ure on either central or lateral areas except an extremely minute and 

 even granulation over the whole surface. The umbo of the posterior 

 valves is unusually near the front margin. 



Interior white, each valve having a pair of posterior rays and a 

 central spot of brown. Sutural plates broad, sinus rather shallow 

 having about 8 teeth. Anterior valve having 25-26, central valves 

 2-3, posterior valve 26-28 slits ; teeth stout, blunt, deeply pectin- 

 ated ; eaves very spongy. 



Girdle covered with coarse flattened-convex scales. 



Length 110, breadth 70 mill. 



Galapagos Is. 



Chiton goodallii BROD., P. Z. S. 1832, p. 25. C. godallii SOWB., 

 Conch. 111., f. 34, 40. C. goodalli REEVE, Conch. Icon., f. 8. 

 Radsia goodalli CPR., MS. 



This very large smooth species is quite, unlike any other. 



C. SULCATUS Sowerby. PI. 28, figs. 1, 2, 3, 4. 



Shell oval or oblong, moderately elevated, carinated, the side- 

 slopes nearly straight ; of a uniform olive-black, or having the 

 lateral areas obscurely purple-black. 



