436 



CALIFORNIA ACADEMY OF SCIENCES 



[Proc. 4th Ser. 



by larger irregularly scattered warts, the lateral areas dis- 

 tinctly defined only in well preserved specimens ; a color pattern 

 of brownish flames or stains sometimes persistent; sutural 

 laminae short and wide, the sinus wide and shallow ; tegmental 

 border straight or only slightly sinuous in front; teeth short, 

 not projecting; eaves spongy; mucro low, nearly median in 

 position; slit formula 8 to 11, 1-1, 9 to 12, the slits and teeth 

 of the tail valve very oblique. 



Recorded Range: 



Pleistocene: Lower San Pedro Series — "Chiton Bed", 

 Point Fermin, California (Chace and Chace, !). 



Living: Monterey, California, to Magdalena Bay, Lower 

 California; between tides. 



Material Examin ed : 



Remarks: This species comes near to being the most 

 abundant chiton now living on the coasts of California south 

 of Monterey, with the possible exception of- Lepidochitona 

 dentiens, and from analogy with other species, one would 

 naturally expect it to occur commonly in the Pleistocene. Such, 

 however, is not the case. As a matter of fact, it has been un- 

 known as a fossil until very recently, and seems to be very rare 

 except at the Point Fermin "Chiton Bed", whence all my speci- 

 mens were obtained. Most of these are too worn to show well 

 the characteristic warty sculpture which in the shells of living 

 animals can usually be relied on to separate hartwegii from all 

 our other chitons. 



