TONICIA. 197 



Chiton elegans FREMBLY, Zool. Journ. iii, p. 203, suppl., pi. 17, f. 

 6. SOWB., Conch. Illustr., no. 75. REEVE, Conch. Icon., t. 4, f. 19. 

 C. sparsus SOWB., Conch. Illustr., f. 73, 74 (young.) 



The type species of Tonicia. The sculpture is well shown in fig. 

 22 ; the color-pattern in the figure between 22 and 24. 



Subspecies CHILENSIS Frembly. PI. 41, figs. 19, 20. 



Shell rather heavier and thicker than T. elegans, with thicker 

 girdle. Color a uniform dark chocolate brown, except near the beaks 

 where there is a large or small area the shape of the valve which is 

 light delicately mottled with reddish ; girdle dark brown, wide at the 

 sides, narrow at the ends. 



The diagonal line is surmounted by a series of small tubercles; 

 lateral areas showing fewer and less conspicuous eye-spots than T. 

 elegans, arid otherwise nearly smooth, the granulation being obsolete ; 

 central areas striated on each side of a median smooth band, and 

 more or less (variously) roughened at the sides ; second valve sub- 

 carinate, striated in the middle. End valves radially, sparsely 

 granulate and dotted with eyes, the umbo of the tail valve obtuse, 

 conspicuous, elevated, a little in front of the middle. 



Interior white, marked with reddish under the beaks. Sinus 

 toothed. Sutural plates broad, especially at the outer-anterior portion. 

 Anterior valve having 7, central valves 1, posterior valve 8 slits; 

 teeth very thick and blunt, strongly, closely pectinated. 



Girdle leathery, naked, rather thick. 



Length 38, breadth 28 mill.; divergence 130. 



Length 68, breadth 43 mill. 



Valparaiso, under stones. 



C. chilensis FREMB., Zool. Journ. iii, p. 204, suppl., pi. 17, f. 8. 

 REEVE, Conch. Icon., t. 3, f. 17. Tonicia chilensis ROCHEBRUNE, 

 Nouv. Arch, du Mus. 1881, p. 240 (Reported from the Canaries, on 

 the authority of specimens so labelled in the Paris Museum, but 

 undoubtedly false.) 



This form is very closely allied to T. elegans, differing mainly in 

 the (a) dissimilar coloration, (6) more numerous stride on each side 

 of the median smooth band, (c) generally obsolete granulation of the 

 lateral areas, (d) thicker insertion-teeth, and in the thicker girdle ; 

 a still better distinction is in the tail-valve, which in chilensis has a 

 more prominent umbo, nearer the center than in elegans, and the area 

 in front of the umbo is striated, whilst in elegans it is smooth. All 



