Vol. XI] BERRY— FOSSIL CHITONS 4gO. 



35. Callistochiton palmulatus mirabilis Pilsbry, 1893 

 (Plate XIV, figs. 9-16; Plate XV.) 



1893. Callistochiton palmulatus var. mirabilis Pilsbry, Man. 



Conch., (1), v. 14, p. 263, pi. 58, f. 7-11. 

 1917. Callistochitoti palmulatus and var. mirabilis Chace, Lor- 



quinia, v. 2, p. 30 (recorded from Pleistocene of 



Santa Monica, Cal.). 



Diagnosis: Valves small, thick, massive, elevated, carinated ; 

 side slopes slightly convex ; lateral areas elevated, divided by a 

 strong median sulcus into two nodulose ribs, each sometimes 

 with a secondary furrow on the summit ; head valve strongly 

 elevated, primarily with 9 strongly tubercular, eventually sili- 

 cate, radial ribs; central areas with 14-18 moderately strongly 



Fig. 11 



Fig. 11. Callistochiton palmulatus mirabilis Pilsbry. Anterior elevation 

 of valve illustrated in Plate XIV, figs. 15-16. 



interlatticed ribs on each side, subparallel except on the jugum 

 of valve ii, where they diverge ; tail valve with mucro in front 

 of middle, the abbreviated central area much lower than the 

 swollen posterior region; sutural plates very short, connected 

 across the shallow narrow sinus; teeth short, curved, slightly 

 projecting in valves i-vii, extremely robust and thick in valve 

 viii; eaves wide, solid; slits 9, 1-1, 18 to 25, with distinct pore 

 lines leading into them. 



Recorded Range: 



Pleistocene: Lower San Pedro Series — Nob Hill Cut, 

 San Pedro, California ( !). 



Upper San Pedro Series — Long Wharf Canyon, Santa 

 Monica, California (Chace, !) ; Los Cerritos Hill, Long Beach, 

 California ( !). 



Formation doubtful — Deadman Island, San Pedro, 

 California ( !). 



