PELECYPODA—PRIONODESMACEA. 



399 



bling both P. tenuistriata and P. fecunda. Differs from both in 

 the strong, lamellose striae with very fine striae intermediate. 

 Hamilton Group : New York, Pennsylvania, Virginia. 



85. P. tenuistriata Hall. (Fig. 510, c.) Devonic. 

 Large, ovate, doubly truncate posteriorly. Surface marked with 



fine and often crowded concentric striae. 



Very abundant in the Hamilton of New York, etc. 



86. P. fecunda Hall. (Fig. 510, k, I.) Devonic. 

 Differs from P. tenuistriata in its more elongate outline and 



coarser striae, while in P. muta the striae are still stronger, being 

 coarse and lamellose. 



Hamilton Group : New York, Virginia, Wisconsin ? 



87. P. plana Hall. (Fig. 510,/.) Devonic. 



Fig. 510. a, 6, Paleoneilo constricia (natural size and enlarged); c, P. tenuistriata , 

 right valve ; d, P. brevis ; e, P. marshallensis, right valve ; /, P. plana, enlarged ; 

 g-i, P. ?nuta, 2 left and I right valve ; /, P. sulcatina ; k, I, P. fecunda ; m-p, 

 P. emarginata. (Pal. N. Y., V.) 



