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EXPLANATION OF PLATES. 



Plate I. 



Dcrhya multistriata (Meek). 



1. iX. h. c. Reproduced from de Kouiuok's, pi. XIII, f. 7, a, b, c. 



2. Figure 7a. pi. XIII bis. of de Koniuck. These specimens are called 

 "Orthis umbraeulum" by him. but are very different from those figured by 

 Bromi, from the Devonian of Eiffel, after examining Schlotheim's types. 



3a. Specimen below average size, but possessing an unusually high 

 hinge area which is symmetrical, posterior view. 

 3b. Lateral profile of same specimen. 

 All figures natural size. 



