EXPLANATION OF PLATE XXXVII. 



Page 



FIG. 1. Productus punctatus 51 



la. Side view. 

 Ib. Dorsal view 

 Ic. Ventral view. 



Carboniferous, Upper Coal Measures. 



FIG. 2. Productus cora 47 



2a. Ventral aspect. * 



2b. Dorsal view. 



2c. Ventral view of another variety. 



Carboniferou , Upper Coal Measures . 



FIG. 3. Productus nebrascensis 48 



3a. Dorsal view. 

 3b. Side view. 

 3c. Ventral view. 



Carboniferous, Upper Coal Measures. 



FIG. 4. Productus longispinus 4& 



4a. Dorsal view. 

 4b. Ventral aspect. 



Carboniferous, Upper Coal Measures. 



FIG. 5. Chonetes lavis 55 



5a. Ventral view of type specimen. 

 6b. Longitudinal section of same. 



Carboniferous, Lower Coal Measures. 



FIG. 6. Chonetes flemingi 54 



6a. Ventral view of specimen with short hinge-line. 

 6b. Ventral aspect of example with long hinge-line. 



