266 Systematic Paleontology — Middle Devonian 



The species is represented by two left valves Avliich appear to be identical 

 with the Marcellus species described by Hall. 



Occurrence. — Romney Formation, Onondaga Member. Eidgeville, 

 W. Va., and Blair County, Pa. 



Collection. — U. S. National Museum. 



[E. M. Kindle.] 



AVICULOPECTEN sp. 



Plate XXXI, Fig. 12 



Description. — A species of Aviculopecten not sufficiently well preserved 

 to permit confident identification is found in the fauna. Its finely can- 

 cellated surface suggests A. cancellatus of the Chemung of New York. 



Occurrence. — ^Romney Formation, Hamilton Member. Hancock. 



Collection. — Maryland Geological Survey. 



Superfamily MYTILACEA 

 Family MODIOLOPSIDAE 



Genus MODIOMORPHA Hall 



MoDioMORPHA CONCENTRICA (Conrad) 

 Plate XXXII, Figs. 5-9 



Pterinea concentrica Conrad, 1838, Geol. Surv., N. Y., An. Rep., p. 116. 



Cypricardites concentrica Conrad, 1841, Geol. Surv. N. Y., An. Rep., p. 52. 



Modiola concentrica Hall, 1S43, Geol. Surv. N. Y., pt. iv, p. 196, fig. 9. 



Modiomorpha concentrica Hall, 1870, Prelim. Notice Lamellibranchiata 2, 

 p. 73. 



Modiomorpha concentrica Hall, 1885, Pal. N. Y., vol. v, pt. i, Lamelli- 

 branchiata ii, p. 275, pi. xxxiv, figs. 9, 10; pi. xxxv, figs. 1-5; pi. xxxvi, 

 figs. 1-16 (17, 18 ?). 



Modiomorpha concentrica Keyes, 1891, Johns Hopldns Univ. Circ, vol. xi, 

 p. 29. 



Modiomorpha concentrica Clarke, 1903, N. Y. State Mus., Bull. 65, p. 448. 



Modiomorpha concentrica Grabau and Shimer, 1909, N. Am. Index Fossils, 

 vol. i, p. 515, figs. 692d, 694d. 



Description. — " Shell of medium size, ovate, extremely variable in its 

 proportions; length less tlian twice the height; basal margin often nearly 



