390 SYSTEMATIC PALEONTOLOGY 



variety resembles .4. staminea, its probable progenitor. The ribs vary 

 from twenty-five to thirty-one, twenty-eight or twenty-nine being quite 

 common. The teeth are fine, narrow, close set and tend to become irregu- 

 lar at the anterior and posterior ends of the dental area. 



Length, 68 mm.; height, 55 mm.; diameter, 28 mm. 



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

 St. Mary's Eiver. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 IT. S. National Museum. 



Subgenus NOETIA Gray. 



Arca (NoiJTiA) iNCiLE Say 

 Plate CVI, Figs. 3, 4. 



Area incile Say, 1834, Jour. Acad. Nat. Sci. Phila., voL iv, 1st ser., p. lo», pL x, tig. 3. 

 Arca incile Courad, 1832, Fossil Sliells of the Tertiary, p. 16, pL ii, tig. 1. 

 Arca incile Courad, 1840, Fossils of the Medial Tertiary, p. 56, pi. xxix, tig. 5. 

 Arca incile Tuomey and Holmes, 1856, Pleioceue Fossils of South Caroliua, p. 35, 



pi. XIV, tigs. 6, 7, 18. 

 Arca incile Emmons, 1858, Rept. N. Car. Geol. Survey, !>. 2S4. 

 Anomalocardia incile Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 580. 

 Anadara incile Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 6. 

 Noetia protexta Conrad, 1875, Rept. N. Car. Geol. Survey, vol. i, app. A, p. 19, pi. 



iii, fig. 5 {fide Dall). 

 Arca (Noetia) incile Dall, 1898, Trans. Wagner Free lust. Sci , vol. iii, pt. iv, p. 632. 



Description. — "■ Shell transversely rhomboidal, with about twent}'- 

 seven ribs ; anterior hinge margin compressed and angulated. 



"Disk prominent from the beaks to the anterior part of the base : ribs 

 with transverse granules; those anterior to the middle alternating with 

 very slender and but little prominent lines, and with a groove on each : 

 anterior margin longer to the base than the posterior end, and contracted 

 in the middle: series of teeth nearly rectilinear, entire; interval between 

 the teeth and the apices with a few transverse lines or wrinkles; a single 

 oblique groove from the apex to a little before the middle, and six or 

 seven narrow ones from the teeth outwards behind the apices : beaks placed 

 very far backward : inner margin crenated : muscular impressions a little 

 elevated, posterior one short: basal margin not parallel with the hinge 

 margin." Say, 1824-. 



