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649 



TERTIARY FAUNA OF FLORIDA 



subtruncate, a little produced below ; hinge with numerous rather crowded 

 subvertical teeth in an uninterrupted series ; inner margin of the valves deeply 

 fluted. Lon. of largest valve 28, alt. 14; of younger valve 18, alt. 8.5, diam. 

 7 mm. 



The larger valves of this rare species are distorted or worn so that 

 a younger one has been selected for figuring. The most conspicuous feature 

 of the shell is the deep sulcation of the beaks, which gives them a bilobed 

 appearance. 



Scapharca (Scapharca) donacia n. s. 

 PLATE 33, FIGURE 13. 



Oligocene marl of Bowclen, Jamaica; Bland. 



Shell small, donaciform, moderately plump, with rather elevated proso- 

 ccelous beaks at about the anterior third ; valves almost similarly sculptured ; 

 left valve with about twenty-four low, strap-like, narrow radial ribs with 

 somewhat wider interspaces ; the ribs are plain, smooth, and entire on both 

 valves ; on the left valve the interspaces are crossed by numerous equidistant 

 elevated lines which do not appear on the ribs ; on the right valve the inter- 

 spaces are only marked by lines of growth ; hinge-line short, cardinal area 

 very narrow, smooth ; anterior end larger, rounded ; posterior end produced 

 and attenuated; hinge-teeth small, similar, slightly divergent; internal margin 

 of the valves with deep short flutings. Lon. 6.8, alt. 4.5, diam. 3 mm. 



This little shell has no very marked characters, but appears to be adult, 

 and not very similar to the young of any of the species associated with it. 



Scapharca (Scapharca) auriculata Lamarck. 



Air,i auriculata Lam., An. s. Vert., vi., p. 43, 1819 ; Reeve, Conch. Icon., Area, pi. vi., 

 fig. 35, 1844. 



? Oligocene of Bowden, Jamaica, Henderson ; Pliocene of Limon, Costa 

 Rica, Gabb; Pleistocene of the Antilles, various collectors. Recent, from 

 Key West to Martinique, in fifteen to forty fathoms. 



The fossil from Bowden seems to be this species, though somewhat worn ; 

 that from Port Limon is certainly the same as the recent shell. 



Section Ar^iini dray. 

 Scapharca (Argina) tolepia n. s. 



PLATE 33, FIGURES 7, 8. 

 .h'i,i />,] -<ita dippy, (icol. Mag., Oct., 1874; not of Say, 1822. 



