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TERTIARY FAUNA OF FLORIDA ' ' 



Aligena minor n. sp. 



PLATE 44, FIGURE 8. 



Miocene of the Natural Well, Duplin County, North Carolina ; Burns. 



Shell small, ovate, oblique, very inequilateral, posterior end shorter and 

 smaller, anterior end produced ; beaks small ; surface of the valves moderately 

 convex, smooth except for incremental inconspicuous concentric lines ; interior 

 polished, faintly radially striate, adductor scars rather large, ligamentary sulcus 

 short, the cardinal tooth strong and prominent. Alt. 3.2, lat. 4, diam. 3 mm. 



This little shell by its oblique form and strong cardinal tooth is easily 

 separated from the rather quadrate smooth young shells of A. cequata which 

 are found in the same bed. It appears to be rather scarce, as only five valves 

 were obtained from a large amount of the marl. 



Aligena elevata Stimpson. 



Montacuta bidcntata Gould, Inv. Mass., p. 59, 1841 ; not of Turton. Wheatley, Cat., p. 5, 



1842; De Kay, N. Y. Moll., p. 232, 1843. 

 Montacuta elevata Stimpson, Shells of N. E., p. 16, 1851 ; Binney's Gould's Inv. Mass., 



p. 86, fig. 396, 1870 ; Tryon, Am. Mar. Con., p. 172, pi. 33, fig. 440, 1873 ; Verrill, Inv. 



An. Vineyard Sd., pp. 394, 688, 1874. 



Cyamium elevatum H. and A. Adams, Gen. Rec. Moll., ii., p. 477, 1858. 

 Tellimya elevata Ball, Bull. U. S. Nat. Mus., No. 37, p. 50, pi. 68, fig. 6, 1889. 

 Kelliopsis elevata Verrill and Bush, Proc. U. S. Nat. Mus., xx., p. 784, pi. 93, figs. 2-4; 



pi. 94, figs. 7, 8, 1898. 



Pleistocene of Pt. Shirley, Boston Harbor, Dall ; recent on the coast of 

 New England, especially south of Cape Cod, and south to New Jersey ; Wheat- 

 ley. 



This is a well-characterized species from which we learn that the resilium 

 carries a lithodesma, which is lost in the fossil species. Usually the ligament 

 is invisible externally, but in some specimens a little fissure over it allows it to 

 be seen. The thickened edge to which the resilium is attached has been spoken 

 of as " tooth-like," but it is only the nymph-like thickening produced where the 

 strain requires special strength in the shell and not otherwise like a tooth. 



The only other species of the group which has been described from the 

 American Tertiary, as far as I have been able to discover, is Aligena Sharpei 

 O. Meyer (Proc. Acad. Nat. Sci. Phila. for 1888, p. 171, fig'd), which came 

 from some point on the west shore of Chesapeake Bay, not precisely determined, 

 but probably from the Miocene. 



