Vol. XI] 



BERRY— FOSSIL CHITOXS 



431 



Family Callochitonidae 



Subfamily Lepidochitoninae 



Genus Oligochiton Berry, new genus 



Chiton with valves of normal form ; insertion plates and 

 teeth present, but very short. Surface of tegmentum smooth. 

 Lateral areas scarcely defined. Sutural plates low and wide, 

 separated by a wide and shallow sinus. Eaves spongy. Slits 

 numerous in the end valves; probably 2 or 3 on a side in the 

 median valves. 



Type: the following species : 



2. Oligochiton lioplax Berry, new species 

 (Plate I, figs. 1-6.) 



Diagnosis: Valves of moderate size, without sculpture ex- 

 cept lines of growth ; lateral areas weakly delimited ; mucro 

 nearly median; slits numerous — 13 in head valve, probably 2 

 or 3 on a side in median valves, about 15 in tail valve; teeth 

 short ; sutural laminae short and broad, well separated. 



Type: A tail valve [S. S. B. 608] in the collection of the 

 department of geology, Leland Stanford Junior University. 



Paratypes: A median valve [607] in the collection of the 

 department of geology, Leland Stanford Junior University, 

 and a head valve [606] in the writer's collection. 



Type Locality: "N. P. 129", Sooke Formation Oligocene, 

 "from conglomerates and sandstones found along the sea cliff 

 between the mouths of Muir and Kirby creeks, west of Otter 

 Point, southern Vancouver Island", British Columbia ; 3 valves. 



Material Examined: 



