Vol. XI] 



BERRY— FOSSIL CHITONS 



461 



Material Examined: 



Remarks: Though so common at the present day, even if 

 often somewhat local, along almost the entire coast of Califor- 

 nia, this very ornate little species is here recognized for the first 

 time as a fossil. The specimens seen are intermediate valves 

 and too characteristic in their well preserved sculpture to be 

 readily mistaken. 



The extraordinary extension of the recent range of the spe- 

 cies as quoted by me above is based on a specimen [597] given 

 me by Mr. Will F. Thompson, who collected it between tides in 

 the Straits of Georgia. 



The specific name is commonly written in the adjective form, 

 gemmea, but as the originally published spelling is permissible 

 as a substantive noun, it is here adopted. 



Subfamily Ischnochitoninas 



Genus Ischnochiton Gray, 1847 



Subgenus Stenoplax Carpenter 1879. 



Section Stenoplax s. s. 



21. Ischnochiton (Stenoplax) fallax Carpenter, 1892 



(Plate VII, figs. 1-3) 



1892. IschiiocJiiton (Stenoplax) fallax Carpenter, in Pilsbry, 

 Man. Conch., (1), v. 14. p. 59, pi. 16, f. 17-18. 



Diagnosis: Valves of moderate thickness, low, evenly arched, 

 outline of all but the tail valve concave behind, not beaked ; 

 lateral areas strongly elevated, these and the terminal areas 

 weakly sculptured by fine radial wrinkles and strongly terraced 

 by the lines of growth ; central areas very minutely, longitudi- 



