112 LESS COMMON SPECIES. 



Less common Chitons include the following briefly 

 described species: 



Leptochiton ritgatiis^ Cpr. Minute, smooth, red- 

 dish; southern. 



Chcetopleura gemma^ Cpr. Small, narrow, highly 

 sculptured, reddish browm. It is sometimes found at 

 Monterey. 



Ischnochitoii Cooperi^ Cpr. Regular, richly sculp- 

 tured, especially on the first valve. Sharply arched, 

 brownish without, light green within; length an inch 

 and a quarter. 



Ischnoplax pectinatiis^ Cpr. Similar to the last, 

 but with a rougher mantle ; southern. 



Callistochiton decoratiis^ Cpr. Small, regular in 

 shape, quite sharp along the ridge, valves richly 

 sculptured, each raised triangle being divided into 

 two or more parts. Reddish or yellowish brown ; less 

 than an inch in length; southern, 



Callistochiton palmidatiis^ Cpr. Small, high arched, 

 valves marked with raised sculpturing. One of both 

 of the end valves are greatly thickened and marked 

 with radiating grooves. Length somewhat over half 

 an inch; dark brown; southern. 



Callistochiton fijnbriattis^ Cpr., is another southern 

 species, similar to the last in form and size; sharply 

 arched, narrow, end valves not much thickened, rare. 



Mopalia Hindsii^ Gray. Low arched, marked with 

 faint sculpturing, mantle border covered with minute 

 scales. Nearly black on the outside but white within. 

 Length from an inch to two inches. The specimens 

 before me were collected at Bolinas, Cal. 



