TRANSACTIONS OF WAGNER 

 1088 



TERTIARY FAUNA OF FLORIDA 



in miniature; the shell is always small (alt. 15.5, Ion. 15.5, diam. 9 mm. for 

 the largest seen), less inflated proportionately than C. inuricatiiin of the same 

 size, with the ribs more compressed and crowded. C. muricatum has not been 

 found in any horizon between Bowden and the Pleistocene, which is in itself 

 a strong reason for doubting whether the older shell is identical with the 

 newer. I therefore propose for it the name of bowdenense, which, if con- 

 necting links should hereafter be found, may be regarded as of varietal value. 



Cardium (Trachycardium) oedalium Dall. 



Cardium muricatum Tuomey and Holmes, Pleioc. Fos. S. Car., p. 64, pi. 19, fig. 2, 1856; 



not of Linne, 1758. 

 Cardium carolincnsis (sic) Conrad, Am. Journ. Conch., Hi., p. 13, 1867; not of Conrad, 



1862. 



Pliocene of Florida, on the Caloosahatchie, Alligator, and Shell Creeks, 

 Dall and Willcox ; of South Carolina, near Darlington, Burns and Holmes. 



Shell suborbicular, moderately inflated, nearly equilateral, with low beaks 

 and a narrow smooth space above the upper anterior rib in each valve ; sculp- 

 ture of twenty-seven to thirty-one rounded triangular ribs, separated by 

 narrow, finely cross-striated channels ; the anterior nine ribs bear on their 

 anterior edge small ovate or reniform disks with convex lower surfaces, on 

 each rib connected together by a raised line ; the nine ribs next posterior bear 

 on their summits a similar series of half funicular projections, which become 

 more and more indented in the median line until on the last of the nine ribs 

 the series is composed of double leaflets instead of a single arch; on the 

 remaining ribs the projections are laid on the posterior side as a single series 

 (on each rib) of subtriangular leaflets oblique or nearly parallel with the rib 

 on which they stand; internal margin deeply fluted, disk sulcate, posterior 

 margin feebly serrate, hinge normal, delicate, shell not very heavy. Alt. of 

 type 30, Ion. 31, diam. 19 mm. Some specimens reach an altitude of 46 mm. 



This is the Pliocene representative of Cardium muricatum, which has not 

 been found in the marls so far, but a close examination will show the very 

 different and much more developed character of the murication. This, how- 

 ever, is found occasionally more or less dwindled; a variety depauperatum has 

 the ornaments represented only by sparse and feeble spinules, which, however, 

 preserve their original form whenever intact. This shows much less varia- 

 tion than C. muricatum in the number of ribs, of which there are almost always 

 thirty-one. In studying the sculpture of this and allied species it is very 



