Report of the State GEOLOGIST. 



51 



when tlic Latter are fossilized. In Schizophobjla there ;i few 

 simple trunks restricted to the median portion of the valves. 



Fig. 183.— Interior of pedicle-valve of Strophondla Benlar impressiona 



and pallia! sinu> 



branching only at their extremities; in such shells the lateral 

 expansions of the valves must have been nourished by sinuses too 

 small to leave their traces on the valves. 



-■"C''i\ '.'-- 



Fl©. 134— Internal cast of brachial valve of Fig. Vib.—Orthis subcarinata. An internal 

 Schizophoria impre&a, v. vascular trunks: cast, showing the pallial sinuses: p, im 

 o, genital markings. pression of pedicle muscle: a, impression 



of diduductor muscles: r, vascular sinuses. 



In Crania and Craniella the sinuses are broad, digitate and not 

 sharply defined, in the one; sinuous and without apparent 

 connection with the other. 



Fig. 186.— Crania anomala : showing the vascular and muscular impressions of attached valve. 



(Davidson. > 



In Lingula and its allies there are two main trunks which con- 

 verge toward the anterior margin of the valves, and give off not 



63 



