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86 1 



TERTIARY FAUNA OF FLORIDA 



small and pointed; general form rounded ovoid; other characters as in the. 

 subgeneric diagnosis. Lon. 6, alt. 5, diam. about 4 mm. 



This is an interesting little shell, intermediate between Tugonia proper, 

 Sphcnia, and Mya. 



Genus PARAMYA Conrad. 

 J'tiniinvii Conrad, Prbc. Acad. Nat. Sci. Phila. for 1860, p. 232 ; for 1862, p. 572, 1863 ; 



Meek, Checkl. Inv. Fos. N. Am., Miocene, p. 12, 1864; Dall, Bull. U. S. Nat. Mus., 



No. 37, p. 70, 1889. 

 ^Tyalina Conrad, Fos. Medial Tert., p. 65, pi. 36, fig 4, 1845 ; not of De Koninck, 1842. 



Shell subquadrate, small, concentrically striated (equivalve ?), inequi- 

 lateral, with beaks anterior to the middle line; hinge with a triangular verti- 

 cally directed pit for the resilium, the lateral borders of the pit sometimes 

 carinated, the basal margin depressed ; no hinge-teeth or external ligament ; 

 the pallial line more or less broken up, as in Saxicava, a feature more promi- 

 nent in the young; pallial sinus none in a strict sense, the pallial line slopes 

 forward from the posterior adductor scar in a right line, joining the basal 

 portion at an obtuse angle without any curve or insinuation ; this part of the 

 pallial line is notably distant from the posterior end of the shell. Type P. 

 subovata Conrad. 



This curious little shell was referred to the Saxicavidce by Conrad, Meek, 

 and Tryon, and to the Corbulidce by the present writer, but its true place 

 seems still uncertain and is likely to remain so until the anatomy is made 

 known. In quite young shells the pallial line is distinctly broken up, in old 

 specimens the original patches have become confluent. If the chondrophore 

 of Mya was turned down into the vertical plane of the valves and the surface 

 of attachment in the opposite valve elevated into the same plane, the result 

 would be analogous to the hinge of l\iramya. There are analogies to be 

 traced in Kastcrotia and Fabagclla. On the whole, I am disposed to think 

 that Paramya should be referred to the Myacida, subject to future correction. 

 I have never seen an indubitable pair of valves, and it is uncertain whether the 

 valves are equal or not, but I am inclined to suspect that they are somewhat 

 unequal. 



Paramya subovata Conrad. 



Myalina subovata Conrad, Fos. Medial Tert., p. 65, pi. 36, fig. 4, 1845. 



Paramva subovala Conrad, Proc. Acad. Nat. Sci. Phila. for 1860, p. 232 ; for 1862, p. 



572, 1863; Meek, Checkl. Inv. F63. N. Am., Miocene, p. 12, 1864; Dall, Bull. U. S. 



Nat. Mus., No. 37, p. 70, 1889. 



