586 PROCEEDINGS OF THE ACADEMY OF 



VENERIDJE. 



CIRCUMPHALUS, Klein. 



Subgenus Lirophora, Conrad. 



C. alhleta. Triangular, thick in substance, with eight broad, prominent, 

 recurved ribs, striated at the base ; ribs without posterior lamina- ; lunule 

 cordate. 



V. latilirata, Tuomey and Holmes (not Conrad). 



Locality. Virginia. 



Distinguished from latilirata by its more numerous and narrower ribs, and 

 larger size. The marginal crenulations are much less distinct, and the umbo 

 broader. 



The subgenus is characterized by broad, thick, recurved ribs. The follow- 

 ing recent species belong to it : Venus tiara, Dill. ; V. paphia, L. ; V. Kellettii, 

 Hinds ; V. varicosa. Sower by ; V. fasciata, Don. 



DIONE, Gray. 



D. densata. Ovato triangular, convex, inequilateral ; umbo somewhat flat- 

 tened, and the substance of shell thick in that part, and more so towards the 

 muscular impressions; pallial sinus strongly defined and rounded; lunule 

 lanceolate; anterior cardinal tooth rather thick ; posterior extremity acutely 

 rounded ; surface polished, with strong lines of growth. Length 2 inches, 



, height 7-10. 



Locality. Petersburg. Va. 



Thicker than albaria, Say, with a less concave lunule margin, aud otherwise 

 very distinct. 



D. Virginiana. Ovate, rather thin, slightly ventricose, inequilateral : lunule 

 long, lanceolate, defined by a slight groove and carinated line ; basal margin 

 profoundly rounded medially; cardinal teeth prominent, compressed. Length 

 4 inch. 7-10, height 3 5-10. 



Locality. Petersburg, Va. 



SCROBICULIIN^E. 

 FABELLA, Conrad. 

 Suboval, inequilateral, posterior side shortest; cardinal teeth in right valve 

 two, anterior one submarginal, straight, rudimentary ; the other thick, re- 

 curved, with a pit behind it ; teeth separated by a profound oblique cartilage 

 pit; left valve with three teeth, the anterior one slightly curved, and a pit 

 behind it, separated from the cartilage cavity by a slightly oblique tooth ; 

 posterior tooth rudimentary and parallel with the hinge margin; musculai 

 impressions near the hinge. 



F. (Amphidesma) constricta, C. 



A small bivalve from the Virginia Miocene. 



Errata. 



Page 561, erase Busycon scalaris. 



563, for " MEGOPTYGMA" read MEGAPTYGMA. 



564, for " caelata" read caelatus. 

 566, for " curtum" read curta. 



566, for " (Odostomea)" read (Odostomia). 



567, for " F. (Cancellaria) biplicifera" read C. biplicifera. 

 570, for " quadricostata" read quadricostatus. 



570, for " duodecenaria" read duodecenarium. 



571, for " (Hidella)" read (lliatella). 



573, for " PeronjEderma" read PeroNjEODerma. 



573, for "fluxuosa" read flexuosa. 



576, for " craticuloides" read craticuloide. 



[Dec. 



