jfAHYLAM) fii:(»i>()(;ic.\r. sci{\'i:v 171 



sliiiii. iiillicr anilely rdiiiidcd; iio.-lcriur siilf inodiiccd, acutely rounded 

 at the exti'i'iiiily ; dorsal niainiii hmi;-, iil)li(|iic. sli;:lillv cui'vcd: Ijeaks 

 ])roiniui'iii ; liiinilc laiiccolalc; dclliicd \>\ a sli;^liily imprt'ssed line. 

 Length. I i, inch; hci.^lit, S-l(i inch."" Conrad, IS IS. 



Tliis spceies is wry ahnndaiil in Ihe Woodstock nu'iidicr of the Xaii- 

 jt'inoy I'onnal ion. 



Lengtli, 30 mm.; width, 18 mm. 



Ocninrnre. — Nanjemoy Foumation. Popes Creek, 1 mile .-onlheast 

 of I'iscataway, Woodstock, Upper ]\Iaill)oio (southwest ol' town near 

 forks of two I'oads). 



Collections. — ]\Iaryland Geological Survey, Johns Hopkins University, 

 Plii1ade]i)hia Academy of Natural Sciences. 



Genus DOSINiOPSIS Conrad 



DosiNioPSis LENTicuLAEis (Rogers). 



Plate XXXV, Figs, la-lg. 



Cijtlierea leiiticnlaru'Rogevs, 1S3U, Traus. Amer. Pliilos. Soc, vol. vi, p. 37;2, p], xxviii, 



tig. 1. 

 Oytherea lenticular is H. C. Lea, 1848, Proe. Acad. Nat. Sei. Phila., toI. iv, p. 99. 

 Artemis lenticularis Conrad, 1853, Proc. Acad. Nat. Sci. Phila., vol. vi, p. 320. 

 Dositiia lenticularis Conrad, 18.54, Proc. Acad. Nat. Sci. Phila., vol. vii, p. 30. 

 Dosiniopsis weekii Conrad, 1864, Proc. Acad. Nat. Sci. Phila., vol. xvi, p. 213, and 



tigure in text. 

 Dosiniopsis lenticularis Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. 

 Dosiniopsis nieekii Conrad, 1865, Amer. Jour. Conch., vol. i, p. 6. 

 Dosiniopsis nieekii Conrad, 1866, Smith. Misc. Coll. (200), p. 6. 

 Dosiniopsis lenticularis Conrad, 1866, Smith. Misc. Coll. (200), p. 6. 

 Dosiniopsis lenticularis Harris, 1894, Amer. Jour. Sci., ser. iii, vol. xlvii, p. 302. 

 Dosi7iiopsis lenticularis Clark, 1895, Johns Hopkins Univ. Circ, vol. xv, p. 5. 

 Dosiniopsis lenticularis Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 78, pi. xviii, 



ligs. la-lg. 



Description. — " Shell large, depressed, discoidal, rather thick, length 

 nearly equal to the breadth; transversely striated; lunule long, ovate, 

 •obscurely detined by a very faint impressed line; umbones rather de- 

 pressed; beaks small, hardly recurved; teeth straight, divergent; cavity 

 of the shell not deep; margin entire. Diameter about two inches." 

 Eogers, 1839. 



The type of the species, as figured and described by Eogers, is a mucli 



