164 CHITON. 



Var. mesoglyptw Pilsbry. PI. 38, figs. 20, 21, 22. 



Olive-brown or brown, unicolored or rayed with brick or blood- 

 red, the latter sometimes predominating. Central areas having a 

 group of longitudinal striae on the dorsal ridge, but smooth or nearly 

 so on the pleura. Smaller than the preceding. 



I have seen a considerable number of this form, which is the 

 " var." described by Sowerby and figured in Conch. Illustr., fig. 41. 

 I am unable to say whether it intergrades with the true subfuscusor 

 not. 



C. BOWENII King. PI. 38, fig. 23. 



Shell large, elongated, elevaced, the dorsal ridge carinated ; red- 

 dish-chestnut, olive, or ashen streaked with olive. Mucro in front of 

 the middle, the slope behind it straight. 



Central areas smooth, sometimes with delicate longitudinal stride 

 at the ridge ; lateral areas elevated, delicately radiately striated, the 

 end valves similarly sculptured. The entire surface is microscopic- 

 ally granulated in quincunx pattern. 



Inside having 13 slits in the anterior, 1 in the central, 17 in the 

 posterior valve; teeth pectinated, eaves small; sinus wide, flat, with 

 12-16 teeth. 



Girdle olive-brown, in all the varieties of valve-coloring ; scales 

 solid, rounded, regularly imbricating, and small for the size of the 

 shell. 



Length 82, width 38 mill. ; divergence 98. 



Length 68, width 32 mill. 



Straits of Magellan. 



Chiton bowenii KING, Zoolog. Journ. v, p. 338 (1831 or 1832). 

 SOWERBY, Conch. Illustr., f. 37. REEVE, Conch., Icon., t. 2, f. 9. 

 SMITH, P. Z. S. 1881, p. 35. ROCHEBRUNE & MABILLE, Moll. Cap 

 Horn, p. 141. 



Distinguished by its comparative smoothness, unusually elongated 

 form, and highly ridged back. 



C. CUMINGI Frembly. PI. 30, figs. 29, 30, 31. 



Shell oval or oblong, elevated, the dorsal ridge angular, side- 

 slopes nearly straight. Whitish or olive, very closely and regularly 

 striped with brown or lead-colored lines which are concentric on the 

 end valves and lateral areas and converge forward on the central 

 areas ; often blotched on some or all of the valves with lead-brown 

 or buff. 



