272 Systematic Paleontology — Middle Devonian 



Occurrence. — Romney Foi?mation, Hamilton Member. On Han- 

 cook-Harrisonville Eoad about 2 miles north of Hancock. 



Collections. — Maryland Geological Survey; New York State Museum; 

 American ]\Iuseum of N'atural History. 



Order ANOMALODESMACEA 



Superfamily ANATINACEA 

 Family PHOLADELLIDAE 



Genus PHOLADELLA Hall 



Pholadella radiata (Conrad) 

 Plate XXXIII, Figs. 14-lG 



Nueulites radiata Conrad, 1842, Jour. Acad. Nat. Sci., Phila., vol. viii, p. 248, 



pi. xli, fig. 16. 

 Pholadella radiata Hall, 1870, Prelim. Notice Lamellibranchiata 2, p. 63. 

 Pholadella radiata Hall, 1885, Pal. N. Y., vol. v, pt. i, Lamellibranchiata ii, 



p. 469, pi. Ixxviii, figs. 15-21; pi. xcvi, flg. 1. 

 Pholadella radiata Clarke, 1903, N. Y. State Mus., Bull. 65, p. 488. 

 Pholadella radiata Grabau and Shimer, 1909, N. Am. Index Fossils, vol. 1, 



p. 528, fig. 716. 



Description. — " Shell from small to medium size, elongate-ovate, cun- 

 eate ; length about twice the height ; basal margin regularly rounded, curv- 

 ing in a greater or less degree according to the age of the individual ; pos- 

 terior extremity more or less obliquely, or sometimes vertically, truncate ; 

 anterior end short, obliquely truncated by the lunule and narrowly 

 rounded below, lunule deep, marked by an abrupt incurving of the 

 margin; escutcheon large and well defined; cardinal line straight; some- 

 times a little concave. Valves, in their usual condition of preservation, 

 moderately convex below and gibbous in the middle; beaks subanterior, 

 prominent, strongly incurved; cincture extending from the beaks to the 

 base of the shell as a marked depression and producing a slight sinuosity 

 in the margin ; umbonal slope prominent, often distinctly angular, extend- 

 ing to the post-inferior extremity; post-cardinal slope gently concave, 

 often marked by a slight fold along the middle or by two or more radii. 

 Surface marked by fine concentric striae and anterior to the cincture 



