340 SYSTEMATIC PALEONTOLOGY 



Subgenus PARVILUCINA Dall. 



Phacoides (Parviluoina) crenulatus (Conrad). 

 Plate XC, Figs. 10, 11, 12. 



Luriiia crenuUita Courad, 1840, Fossils of the Medial Tertiary, p. 39, pi. x.\, tig. 2. 

 L^icina lens H. C. Lea, 18-45, Trans. Araer. Pbilos. Soc, vol. ix, p. 340, pi. xxxiv, tig. 



19. 

 Lucbia crennlata Tuomey and Holmes, 18.56, Pleioeene Fossils of South Carolina, 



p. 60, pi. xviii, tigs. 14, 15. 

 Lucina. crennlata Emmons, 1858, Kept. N. C. Geol. Survey, p. 391, tig. 217 (tig. 



poor). 

 Lucina crennlata Courad, 1863, Proe. Acad. Nat. Sci. Phila., vol. xiv, p. 577. 

 Lucina crennlata Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 8. 

 Not Lticina creiiulaia Whitfield, 1894, Mon. xxiv, U. S. Geol. Survey, p. 63, pi. x, 



tigs. 7-15. 

 riuicoides {Parvilucina) crenulntun Dall, 1903, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. vi, p. 1383, pi. Iii, tig. 12. 



Description.— '^' Shell lenticular, with nitmerons concentric laminae; a 

 snbmarginal fold on the posterior side; posterior extremity trnncated; 

 cardinal line straight, oblique; beaks central; cardinal and lateral teeth 

 distinct; margin minutely crennlated." Conrad, 1840. 



Shell orbicular in outline and highly convex or elevated; usually 

 rather thin; hinge area not heavy or broad; anterior side not produced. 

 For distinction from P. trisulcatus see remarks under that species. 



Whitfield has figured as L. crenulata some of the smoother and more 

 rounded forms of P. trisulcatus. 



Length, 6.2 mm.; height, 6 mm.; diameter, 1.8 mm. 



Occurrence. — St. Mary's Formation. Cove Point, Langley's Bluff, 

 St. Mary's Eiver. Choptank Formation. Governor Run, 2 miles south 

 of Governor Eun, Flag Pond, Jones Wharf, Turner, Pawpaw Point, 

 Trappe Landing, Peach Blossom Creek, Dover Bridge, Greensboro, Cor- 

 dova. Calvert Formation. Chesapeake Beach, 3 miles south of Che. - 

 apeake Beach, Plum Point, Reed's. 



Collections. — Maryland Geological Survey. Johns Hopkins University. 



Phacoides (Parvilucina) prunus Dall. 

 Plate XC, Fig. 13. 



Phacoides {Parvilucina) prunus Dall, 1903, Trans. Wagner Free Inst. Sci., vol. iii, 

 pt. vi, p. 1384, pi. Iii, fig. 8. 



Description. — " Shell resembling P. crenulatus but flatter, more in- 

 equilateral, with thicker and more regular concentric ribs, no radial 



