Vol. XI] 



BERRY— FOSSIL CHITOXS 



457 



tern" of regular, flat, scale-like pustules; jugal tract sculptured 

 with 8-12 (fewer in juvenile specimens), closely placed, low, 

 flattened, diverging ribs, separated by narrow, incised grooves ; 

 sutural laminae large, rounded ; jugal sinus moderate; tail valve 

 with mucro nearly median but strongly directed posteriorly; 

 teeth very long and projecting, slit in only a little way; eaves 

 scarcely developed; slits 5, 1-1, 1-1. 



Recorded Range: Pleistocene: Upper San Pedro Series — 

 Long Wharf Canyon, Santa Monica, California ( !). 



Living: 6 miles north of Santa Monica, California (E. P. 

 Chace, coll.,!), to San Diego, California; between tides to 20 

 fathoms. 



Material Examined: 



Remarks: A single fragment of a median valve, still show- 

 ing, however, its characteristic sculpture, was among Dr. 

 Clark's material from the Santa Monica Pleistocene. The con- 

 dition of the specimen leaves much to be desired, but the 

 scaly sculpturing of the central areas, reminding one of a bit 

 of rattlesnake skin, is unlike that of any other of our chitons. 



The species has not been previously recorded as a fossil, and 

 even in the recent state it seems to have an unusually limited 

 geographical range. 



Genus Cryptochiton Middendorff, 1847 

 (also of Gray, 1847) 



19. Cryptochiton stelleri (Middendorff, 1846) 

 (Plate VI, figs. 10-12.) 



1846. Chiton stelleri Middendorff, Bull. Ac. Sci. St. Petersb., 



VI, p. 116 (fidePilsbry). 



1847. Chiton (Cryptochiton) stelleri Middendorff, Malac. 



Ross., I, p. 93, pi. 1-9. 



