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977 



TERTIARY FAUNA OF FLORIDA 



Psammobia (Gobrasus) Wagneri Dall. 



PLATE 25, FIGURE 10. 

 Psammobia (Gobraus) Wagneri Dall, Trans. Wagner Inst., iii., part iv., p. 920, pi. 25, 



fig. 10, 1898. 



Shell moderately elongated, thin, somewhat compressed, the anterior end 

 shorter, both ends rounded ; posterior dorsal margin straight, with an almost 

 linear escutcheon ; surface concentrically sculptured in harmony with the lines 

 of growth, middle of the disk almost smooth, the lines a little stronger anteriorly, 

 on the posterior end periodical, rising in subequally spaced sharp, thin, low 

 lamellae ; nymphs about half the length of the posterior dorsal margin ; hinge 

 L -" 1 , the anterior teeth stronger ; pallial sinus not reaching the vertical of the 



R. 1010 



beaks, round in front, rather narrow, and partly free from the pallial line 

 below ; valves gaping slightly at both ends. Lon. 77, alt. 40, diam. 20 mm. 



Pliocene marls of the Caloosahatchie, Florida, and the Waccamaw River, 

 South Carolina ; Dall and Johnson. 



This fine species is similar to, but smaller than, the Pliocene P. edentula 

 Gabb of California, which reaches a length of one hundred and twenty-five 

 millimetres. 



A number of species have been referred, chiefly by the earlier authors, to 

 Psammobia which do not belong to that genus as now understood. Of these 

 Gari texta Gabb, of the Tejon, and Gari alata Gabb, from the Pliocene of Cali- 

 fornia, appear to belong to Sanguinolaria; P. lusoria Say is a Macoma; P. 

 mississippiensis Conrad, of the Vicksburgian, is probably an Abra or a Semele; 

 Psammocola regia H. C. Lea, of the Miocene, is an Asaphis, while P. lucinoides, 

 of the same author and locality, is perhaps a Diplodonta; Psammocola pliocena 

 of Tuomey and Holmes is a mere individual mutation of P. regia Lea, and 

 both are referable to Asaphis centenaria Conrad ; Psammobia perovata Conrad, 

 of the Vicksburgian, is an Abra. 



With the exception of P. Blainvillei Lea, the Claibornian species are un- 

 figured and the descriptions very inadequate. P. eborea Conrad is a Gobr&ns, 

 not unlike P. papyria Conrad. It is thirty-five millimetres long and nineteen 

 high. Though Conrad describes the posterior end as the longer, the type is 

 almost exactly equilateral, and the truncation of the posterior end is not more 

 evident than in P. Wagneri. It has been referred to P. Blainvillei Lea by 

 Heilprin, probably through some inadvertence, since the outlines are not at 

 all similar. P. filosa Conrad belongs to the section Garum of the typical 

 Psammobias. It is elongated and somewhat arcuate ; the concentric sculpture 

 pretty close and uniform on the disk, but elevated into low, somewhat broken 



