TRANSACTIONS OF WAGNER 



1472 



TERTIARY FAUNA OF FLORIDA 



This has no resemblance to marylandicus but is more nearly like the ante- 

 striatus group of species. 



Crassatellites (Scambula) chipolanus n. sp. ? 

 Plate 49, Figure 12. 



Oligocene of the Chipola beds at Alum Bluff and on the Chipola River, 

 Calhoun County, Florida. 



Shell subtrigonal, solid, in general form resembling C. jamaicensis, but 

 with the nepionic shell small and smooth or concentrically striate, followed by 

 from two to four conspicuous rather distant concentric undulations, after which 

 the whole surface (except the posterior dorsal area) is iinely, closely, concen- 

 trically ribbed ; other characters as in C. jauiaicensis. Lon. 44, alt. 33, diam. 

 18 mm. 



A variety approaches C. jamaicensis still more nearly by having the ribs 

 obsolete on the middle of the disk. There is, as far as our material goes, no 

 gradations between the two forms in the matter of the nepionic sculpture, but 

 if further researches should demonstrate that such a gradation exists, this form 

 would stand as a variety, chipolana, of the Jamaican shell. 



Crassatellites (Scambula) densus Dall. 

 Plate 39, Figures 9, 10, 11, 12. 

 Crassatellites densus Dall, Trans. Wagner Inst., iii., pt. v., p. 119S, pi. xxxix., figs. 9-12, 

 1900. 



Oligocene of the Oak Grove sands, at Oak Grove on the Yellow River, 

 Santa Rosa Covrnty, Florida ; Burns. 



Shell elongate, plump, solid, and thick, the anterior end slightly shorter, 

 the valves subequal ; anterior end rounded, posterior end briefly truncate, sub- 

 rostrate ; Kmule and escutcheon subequal, lanceolate, deeply impressed ; beaks 

 high, full, flattened at the apex ; nepionic shell flat, apically smooth, with about 

 five low, sharp, concentric rather distant waves, followed on the anterior slope 

 by fine, close, concentric threading ; the remainder of the shell smooth except 

 for incremental lines ; posterior dorsal area bounded by a rounded radial ridge, 

 in front of which the shell is slightl}- constricted ; halfway between this ridge 

 and the border of the luntile is a second radial ridge bvit more faint ; hinge 

 normal, laminar grooves and adductor scars deep ; internal margins of the 

 valves smooth. Lon. 50, alt. 35, diam. 26 mm. 



This is well-marked and elegant, recalling on a smaller scale the Miocene 

 C. turgidulus. 



