TRANSACTIONS OF WAGNER 

 976 



TERTIARY FAUNA OF FLORIDA 



Subgenus Gobraus Leach, Moll. Gt. Brit., 1852, p. 265. Type G. variabilis 

 Leach = Solen vespertinus Gmel. 



Shell inflated, more or less truncate behind ; concentrically striate or nearly 

 smooth, often with fine radial striae, especially evident on the posterior dorsal 

 region ; teeth variable, not more than three in the right and two in the left 

 valve ; sinus rounded in front, rarely shorter than the vertical of the beaks, 

 and often more or less detached from the pallial line. 



This group has no circumscription of the dorsal areas, and differs from 

 Psammobia most obviously in its blunt and inflated form, with a distinct pos- 

 terior gape. Chiefly recent. 



? Section Psammobella Gray, 1851. Type P. tellinella Lam. 

 Shell small, with feeble hinge, the sinus coalescent below. 



Section Psammotccna Ball. Type P. effusa Lam., Parisian Eocene. 

 Shell resembling Psammobella, but with the sinus largely free from the 

 pallial line. 



The Psammobias begin in the Cretaceous of America (P. cancellato-scidpta 

 Roemer, Texas, and P. obscura White, Washington), and so far all known 

 North American species belong to the subgenus Gobraus, except two in the 

 Claibornian. 



In the Lignitic or Chickasawan stage of the Eocene is found P. ozarkana 

 Harris; in the Claibornian P. Blaini'illei Lea (as Solecurtus), P. chorea and 

 P. filosa Conrad, and on the Pacific P. Hornii Gabb (as Tellina), of the Tejon, 

 and P. obscura White, of the Puget Group. In the Jacksonian appear P. eborea 

 Conrad and P. papyria Conrad, which seems to extend through the Vicks- 

 burgian (which also has P. lintea Conrad) to the Chipolan Oligocene. The 

 cold water of the Miocene seems to have excluded the genus on our south- 

 eastern coast, but with the warmer temperatures of the Pliocene came P. Wag- 

 neri Ball in Florida and P. edentula Gabb (as Siliquaria) on the Pacific. The 

 latter has persisted in deep water to the recent stage, being joined in the 

 Pleistocene by P. calif arnica Conrad (-\-rubroradiata Carpenter), also found 

 recent. The genus has retreated from the North American Atlantic shores in 

 the present epoch, though a single species, P. vaginata Reeve, is doubtfully 

 reported from Charlotte Harbor on the Gulf coast. P. circe Morch and 

 another unnamed species are extremely rare in the Antilles, while two or three 

 very rare forms, such as P. maxima Beshayes, P. fucata Hinds, and P. rcgidaris 

 Carpenter, are found between California and Panama on the Pacific coast. 



