TONICIA. 199 



somewhat resembles Tonicella lineata Wood (see p. 42, pi. 11, figs. 

 25-28), but differs sufficiently in sculpture and the possession of 

 black eye-pits, as well as in the entirely different insertion-plates. 

 T. swainsoni resembles lineolata in color-pattern, but it differs 

 entirely in having the entire central areas longitudinally, and the 

 lateral areas and end valves radially costulate. 



T. FASTIGIATA (Gray) Sowerby. PI. 41, fig. 21 ; pi. 42, figs. 36, 



37, 38, 39. 



Shell oblong, moderately elevated, subcarinated ; the side-slopes 

 nearly straight ; surface smoothish. Color olive-brown, sometimes 

 whitish, having indistinct concentric darker streaks ; rarely unicolored 

 black-brown. 



Lateral areas hardly raised, indistinctly separated from the central 

 areas by a smooth, low or obsolete diagonal ridge. Entire surface 

 of lateral and central areas covered with a microscopic granulation, 

 the granules sometimes coalescing into short wrinkles in front of the 

 diagonal at the sides. Dorsal ridge having a very narrow smooth 

 band in the middle, on each side of which there are several deeply 

 engraved longitudinal grooves. Second valve either smooth or 

 having a group of striae in the middle. End valves showing numer- 

 ous rays of eyes ; the mucro of the posterior valve prominent, in 

 front of the middle. 



Interior white, marked under the apex or suffused throughout the 

 jugal tract with reddish. Sinus toothed. Anterior valve having 7, 

 central 1, posterior valve 10 slits; teeth rather thin, crenulated out- 

 side and at the edge. 



Girdle leathery, nude, dark brown. 



Length 54, breadth 34 mill. ; divergence 110. 



Length 48, breadth 26 mill.; divergence 110. 



Sts. of Magellan. 



C.fastigiatus GRAY, in SOWB., Conchol. Illustr., f. 11, 35. REEVE, 

 Conch. Icon., f. 26. SMITH, P. Z. S. 1881, p. 35. 



? Chiton cliiloensis SOWB., P. Z. S. 1832, p. 58 ; Conch. 111. (as syn. 

 of elegans), f. 13*, 10, 29, 30. REEVE, Conch. Icon., t. 3, f. 14. 



The main distinguishing characters of this species are its even fine 

 granulation, lack of tubercles on the low diagonal ridge, few 

 engraved grooves on each side of the smooth narrow dorsal band, 

 and the obscure concentrically streaked style of coloration. 



