TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



Shell large, irregular, taking the form of the object to which it adheres, 

 the upper valve convex, with rude, irregular radial threads or unequal riblets, 

 close-set and frequently broken up so as to appear vermicular; interior 

 smooth, with two muscular impressions rather feebly impressed, the site of 

 the rcsilium deeply impressed and extending behind the cardinal margin; 

 attached valve concave, irregular, the foramen small and elongate, probably 

 eventually closed, the chondrophore projecting partly over it in our specimens ; 

 space between the valves very small. Alt. 44, lat. 58, diam. 7 mm. 



This species is one of the few characteristic fossils which are preserved 

 at Rock Bluff, and has not occurred at Oak Grove or Alum Bluff in the same 

 horizon, which may be explained by the fact that the bed at Rock Bluff is an 

 old oyster reef, in which only Ostrea, Turritella, the present species, and frag- 

 ments of Peclen and Balanus are preserved. The matrix is ill adapted to 

 conserve fossils in their perfection, and the specimens of Pododesmus are very 

 irregular and mostly shattered by internal .movements of the marl. 



Section Mania Gray. 



Pododesmus (Monia) macroschisma Dcshayes. 

 Anomia macroschisma Desh., Rev. Zool. Soc. Cuvierienne, p. 359, 1839; Mag. Zool., 



1841, pi. 34; Middendorf, Beitr. Mai. Ross., iii., p. 6, 1849; i' 1 " 1 -. Abbild. beschr. 



Conch., p. 132, pi. i, fig. 4, 1850. 

 Placunanomia macroschisma Gray, P. Z. S., 1849, p. 121 ; Cat. Anom. Brit. Mus., p. 



12, 1850 ; Cpr., Rep. Brit. As., 1863, p. 646. 

 Placunanomia cepio Gray, P. Z. S., 1849, p. 121 ; Cat. Anom. Brit. Mus., p. II, 1850; 



Reeve, Conch. Icon., pi. 3, fig. 12, 1859. 

 Placunanomia alope Gray, op. cit., p. 122, 1849; Reeve, Conch. Icon., pi. 3, fig. u. 



Upper Miocene of Sooke, Vancouver Island, C. F. Newcombc ; Plio- 

 cene of San Diego, California, Hcmphill ; Pleistocene of California, Oregon, 

 and Alaska, Dall ; recent from North Japan to Kamchatka, the Aleutian 

 district and southeastern Alaskan coasts south to Lower California in shallow 

 water. 



This species is abundant in the Pleistocene and occurs in the California!! 

 Pliocene of the San Diego well. It is a very large, solid, and characteristic 

 species. Carpenter referred a fossil of the Carri/.o Creek Miocene, Anomia 

 subcostata, to this species, but the sitbcostata is a true Anomia. It is possible 

 that Placunanomia inornata Gabb, referred by him to the Cretaceous and by 

 Conrad to the Tejon Eocene, may belong in this section, and it even greatly 

 resembles this species externally (cf. Pal. Cal, p. 217, pi. 32, figs. 288, 288 a, 



