138 BULLETIN" 00, UNITED STATES NATIONAL MUSEUM. 



Section BELLUCINA Ball. 

 PHACOIDES (BELLUCINA) TAMPAENSIS, new species. 



Plate 21, figs. 1, 2. 



Shell small, trimccate-ovate, moderately plump, eqiiivalve, slightly 

 inequilateral, strongly sculptured; beaks small, low, closely adjacent, 

 slightly prosocoelous ; anterior dorsal slope excavated with a deeply 

 impressed cordate lunule, smooth and large for the size of the shell ; 

 posterior slope direct, with a narrow, hardly depressed lanceolate 

 escutcheon; posterior dorsal area compressed, bordered below by a 

 shallow wide sulcus which is indicated at the posterior margin by a 

 shallow excavation ; anterior end broadly rounded, posterior subtrun- 

 cate, base evenly arcuate; beaks slightly nearer the posterior end of 

 the shell; radial sculpture of (on the type-specimen eleven) rather 

 wide, low, convex, feeble ribs separated by narrower intervals, the 

 ribs sometimes duplex and then narrower; concentric sculpture of 

 low, elevated, narrow lamellae, more crowded on the beaks and near 

 the base, more distant on the middle of the valves, overriding the 

 ribs and intervals; interior of the valves with a strongly crenulate 

 margin; the hinge inaccessible. Length of shell 5 mm., beaks behind 

 the anterior end 2.7 mm., height 4 mm., diameter 2.5 mm. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida. 



Type-specimen from the Post collection, U. S. Nat. Mus. No. 

 165202. 



Section CAVILTJCINA Fischer. 



Cavilucina Fischer, Mau. de Conchy!., 1887, p. 1143, Type, Lucina sulcata 

 Lamarck.— Dall, Trans. Wagner Inst., vol. 3, pt. 6, p. 1361, 1903. 



PHACOIDES (CAVILUCINA) RECURRENS Dall. 

 Plate 24, fig. 3. 



Phacoides (Cavilucina) recurrens Dall, Trans. Wagner Inst., vol. 3. pt. 6, 

 p. 1369, pi. 52, fig. 11, 1903. 



Oligocene of the silex beds at Miami; of the lower bed at Alum 

 Bluff, Chattahoochee River; of the Chipola marl on the Chipola 

 River, Calhoun County, Florida; and of the Bow den beds, Jamaica, 

 West Indies. U. S. Nat. Mus. No. 114685. 



Subgenus LUCINISCA Dall. 



Lucinisca Dall, Synopsis Lucinacea, Proc. U. S. Nat. Mus., vol. 23, No. 

 1237, p. 805, 1901. Type, Lucina naftsula Conrad.— Dall, Trans. Wag- 

 ner Inst., vol. 3. pt. 6, p. 1361, 1903. 



PHACOIDES (LUCINISCA) PLESIOLOPHUS Dall. 



Phacoides (Lucinisca) plesiolophus Dall, Trans. Wagner Inst., vol. 3, 

 pt. 6, p. 1371, pi. 40, figs. 2, 5, 1903. 



Oligocene sands of Oak Grove, Florida, and the Tampa silex beds. 

 U. S. Nat. Mus. No. 166110. 



