236 NEW FOSSIL SHELLS 



FAMILY 



GENUS SOLEN. 



S. MAGNODENTATUS, PL. 34. FlG. 8. 



S. testa anticl truncatd, et valde hiante, lavi, politd, crassd; natibus compressis; dente latcrali uno; dente cardinali uno, 

 longo, acuto. 



Shell truncate, and gaping very much anteriorly, smooth, polished, thick; beaks compressed; with one lateral, and 

 one long, acute, cardinal tooth. 



Diam. _ . Length . Breadth 



Remarks. Although I possess but a small fragment of this shell, yet it differs sa 



essentially in the teeth from all of our Solenes, that I have no hesitation in pronouncing 



it distinct. I believe that it is the only extinct fossil species as yet found in our 

 Tertiary. 



GENUS PANOP^EA. 

 P. DUBIA, PL. 34. FIG. 9. 



P. testa quadrato-ellipticd, transverad, iruequilaterali, postice truncatd, antice rotundatd } sub-inflatd, crassiusculdj striatd; 

 striis concentricis, regularibus; margine basali recto; margine dorsdi recto; nymphis wiagm's, exsertis, longissimis; car dine 

 cochlea parvd. 



Shell quadrately elliptical; transverse, inequilateral, posteriorly truncate, anteriorly rounded, somewhat inflated, ra- 

 ther thick, striate; strise concentric, regular; basal margin straight; dorsal margin straight; beaks prominent; nymphae 

 large, exserted, very long; hinge with a small fosset. 



Diam. .10 of an inch. Length .08. Breadth 



Remarks. The nymphae are unusually large, much exserted, and very long, extending 

 the whole length of the dorsal margin. Near the beak, they are suddenly depressed and 

 twisted round, and terminate in a small, shallow, internal fosset, or spoon-shaped tooth. 



It is not without some hesitation that I have placed this shell among the Panopseee, as 

 it has a spoon-shaped tooth in place of an erect, pointed one, but there is no genus to 

 which it can be said positively to belong, and I do not consider its peculiar characters 

 sufficient to authorize the erection of a new one for its reception. It seems to connect the 

 Glycymeris with the Anatina, having the nymphaB of the one, and the spoon-shaped 

 tooth of the other. 



FAMILY MYID^E. 



GENUS MYA. 

 M. REFLEXA, PL. 34. FIG. 10. 



M. testa quadrilaterdi, sub-inaquilaterali, postice rotundatd, antice truncatd et valdi apertd, inflatd, striatd; striis concen- 

 tricis, irregularibus; clivo umboniali elevato, rotundato; margine basali curvato; margine dorsali arcuato; natibus prominen- 

 tibus, incurvis. 



Shell quadrilateral, somewhat inequilateral, rounded posteriorly, truncate and very open anteriorly, inflated, 

 striate; striae concentric, irregular; umbonial slope elevated, rounded; basal margin curved; dorsal margin arcuate; 

 beaks prominent, incurved. 



Diam. .18 of an inch. Length .22. Breadth .29. 



Remarks. The opening at the anterior portion of the shell is remarkably large, and 

 the margin there appears to be somewhat reflected. The striae are more numerous and 

 better characterized at the extremities, than in the central portion of the shell. 



