Maryland Geological Survey 433 



Family CCELOSPIRIDAE 



Genus ANOPLOTHECA Sandberger emend. 



In America these shells are usually known as Coelospira and Leptocoelia. 

 Schuchert' referred them all to Auoplotheca, holding that there is not 

 sufficient difference between the American and European species to war- 

 rant generic or even subgeneric separation. Eegarding Coelospira and 

 Anoplotlicca Hall and Clarke state that " the only material difference, 

 that can now be indicated between these forms, is one of greater geological 

 than biological significance; the later, or middle Devonian forms (Ano- 

 plotheca) being more convex, more coarsely and sparsely plicated, and 

 more strongly striated concentrically." Eegarding Leptocoelia they write : 

 " In general contour, structure of hinge, cardinal process, muscular scars, 

 and internal septa, it agrees throughout with Anoplotheca and Coelospira." 

 Leptoccelia fiahellites differs from Coelospira concava " only in its greater 

 size and coarser, simple plication of the surface." Certainly none of these 

 differences are worthy of subgeneric rank. However, these shells can be 

 divided into two natural groups on the basis of the contour of the dorsal 

 shell. In one group it is concave, and in the other flat or convex. It is not 

 known that the two groups blend, and there may be more significance in 

 the form of the dorsal shell than can now be made out. For this reason 

 the species may be arranged as follows : 



Anoplotheca. Dorsal valve concave. 



A. concava (Hall). New Scotland. 



A. dichotoma (Hall). Oriskany. 



A. equistriata Schuchert. Oriskany. 



A. Camilla (Hall). Oriskany and Onondaga. 



A. lepida (Goklfuss). Middle Devonian of Europe. 



A. venusta (Schnur). Middle Devonian of the Eifel. 



Leptocoelia. Dorsal valve flat or convex. 



L. acutiplicata (Conrad). Onondaga. 



L. fimbriata Hall. Oriskany. 



L. flabellites (Conrad). New Scotland to Onondaga. 



L. infrequens (Walcott). Lower Devonian. 



Leptocoelia hemispherica (Sowerby) lial], L. planoconvea-a (Hall), and 

 L. plicatula (Hall) of the Clinton probably belong to a genus distinct 

 from Anoplotheca and Leptoccelia. 



' Bull. U. S. Geol. Surv., No. 87, 1897. 

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