GASTROPODA— MITRIDJE. 



789 



Miocenic of the Carolinas and Virginia; Pliocenic of South 

 Carolina and Florida; Recent off Carolina coast. 

 590. M. denticulata Conrad. (Fig. 11 53, b.) Miocenic-Recent. 



Small ; spire high for the genus, of about 5 regularly enlarging 

 whorls, nearly flat, with suture slightly depressed ; body whorl nar- 

 rowing towards front; aperture narrow and ovoid, widest in the 

 middle, with four strong plicae on columella and denticulations on 

 the outer lip ; no anterior notch. 



Chesapeakean of Maryland and Virginia; Caloosahatchie beds 



FlG. 1 153. a, Marginella minuta ; b, M. denticulata. (Md. Survey.) 



(Pliocenic) of Florida; Recent from Cape Hatteras to Florida and 

 Barbadoes. 



Family Mitrid^e. 



CLXXXIII. Mitra Lamarck. 



Differs from Marginella in having its spire drawn out, so as to 

 be longer than aperture, which is slightly notched anteriorly. 

 Tertiary-Recent. 

 591. M. holmesii Dall. (Fig. n 54.) Pliocenic. 



Spire about twice the length of aperture; sutures moderately 

 depressed; whorls somewhat flattened and marked by strong, nar- 



FlG. 1 154. Mitra holmesii, X 8. Fig. 1 155. Conomitra staminea, X I -^ < 

 (After Dall.) (After Dall.) 



row ribs about twice their width apart. Columella with three pli 

 cations, the posterior straight; spirals rounded, equal. 



