TRANSACTIONS OF WAGNER 



35 TERTIARY FAUNA OF FLORIDA 



in front of the posterior end ; both ends rounded, base arcuate, lunule narrow, 

 lanceolate, no distinct dorsal areas; sculpture of numerous even, fine, close- 

 set, rarely divaricate, similar radial riblets, crossed by fine, rounded, equal,- 

 close-set threads, narrower than the riblets, and which in crossing the latter are 

 slightly arcuate convexly towards the beaks, making a very elegant though 

 minute type of sculpture ; hinge thin and delicate, but the teeth, especially the 

 right laterals, very distinct ; scars normal ; margins delicately crenulate. 

 Height 9.5, length 11.5, diameter 4.5 mm. 



This species is of the fully differentiated Jagonia type and its sculpture is 

 notably elegant. 



Oodakia (Jagonia) speciosa Rogers. 

 Lucina speciosa Rogers, Trans. Am. Phil. Soc., N. S., v., p. 333, pi. xxvi., fig. 6, 1837; 



not of Reeve, Conch. Icon., 1850. 

 Lucina squamosa Conrad, Fos. Med. Tert., p. 38, pi. xx., fig. I, 1840 (not of Lamarck, 



1818) ; Tuomey and Holmes, Pleio. Fos. S. Car., p. 57, pi. xviii., figs. 6, 7, 1857; 



Emmons, Geol. Rep. N. Car., p. 291, 1858. 

 Codakia speciosa Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 577, 1863. 



Miocene of Virginia at Yorktown on the York River and City Point on 

 the James River ; upper Miocene of Magnolia and the Natural Well in Duplin 

 County, North Carolina ; of Darlington and the Ashley River limestone, South 

 Carolina ; Pliocene of the Caloosahatchie and Shell Creek, Florida ; Willcox, 

 Burns, and Dall. 



This species resembles in a general way the C. orbiculata Montagu and 

 passes through an analogous series of mutations, but the adults never attain 

 the size of the recent species ; they have a relatively somewhat larger lunule 

 and coarser marginal crenulation; they are also usually somewhat less com- 

 pressed. 



On the whole, it seems best to retain Rogers' name for the shell, which is 

 widely distributed through the upper Miocene and Pliocene of Virginia and 

 southward, though I have not yet seen it from the typically cold-water Chesa- 

 peake Miocene of Maryland. 



Oodakia (Jagonia) orbiculata Montagu. 

 Venus orbiculata Montagu, Test. Brit. Suppl., p. 42, pi. xii., fig. i, 1808; Dillwyn, Descr. 



Cat. Rec. Sh., i., p. 192, 1817. 

 Lucina squamosa Lamarck, An. s. Vert., v., p. 542 (after Enc. Meth., ii., pi. cclxxxv., figs. 



3a-c), 1818; not of Lamarck, Ann. du Museum, vii., p. 240, 1806. 



