Vol. XI] 



BERRY— FOSSIL CHITONS 



437 



5. Cyanoplax fackenthallae Berry, 1919 



(Plate II, figs. 9-10.) 



1919. Cyanoplax fackcnthallce Berry, Lorquinia, v. 2, p. 45 [5]. 



Diagnosis* Valves low, relatively short and wide, median 

 ones distinctly beaked ; sculpture comprising a fine, close, sha- 

 green-like, quincuncial granulation over the entire surface, and 

 a few rather irregular grooves on the terminal areas; lateral 

 areas rather poorly defined; color pale, usually without mark- 

 ings; sutural laminae triangular, projecting well forward, the 

 sinus wide and deep; tegmental border sinuous in front; teeth 

 of head and median valves very long and projecting, the slits 

 extending only part way to base, in tail valve projected some- 

 what anteriorly, those on the sides of this valve oblique and 

 distinctly pointed; eaves spongy; mucro low, somewhat pos- 

 terior; slit formula 8, 2-2 ( ?), 11. 



Recorded Range: 



Pleistocene: Lower San Pedro Series — Chiton Bed, 

 Point Fermin, California ( !). 



Living: Pacific Grove, California; between tides. 



Material Examin ed : 



Remarks: The single head valve seen seems to be conspe- 

 cific with a similarly unique recent specimen at hand from Pa- 

 cific Grove, which I recently ventured to describe as new under 

 the name given above. It is also very near to another recent 

 species lately described from Southern California, the C. lozvei 

 (Pilsbry), but the fossil agrees rather better in its lack of lines 

 of pores in the articulamentum and in the more solid nature 

 of the eaves and other parts of the shell, with the Pacific Grove 

 form. 



* It has been necessary to draw a portion of this description from a recent 

 specimen. 



