TRANSACTIONS OF WAGNER 

 I I ^2 



TERTIARY FAUNA OF FLORIDA 



narrow, teeth normal, very small ; interior feebly radially striate. Lon. 9.5, 

 alt. 6, diam. 2.5 mm. 



A single valve of this beautiful species was obtained in the marl. 



Bornia Mazyckii Dall. 



PLATE 25, FIGURE 8. 

 Bornia Mazyckii Dall, Trans. Wagner Inst., iii., part iv., p. 920, pi. 25, fig. 8, 1898. 



Pliocene marls of the Caloosahatchie River, Florida ; Dall. 



Shell ovate, compressed, subequilateral, faintly concentrically striated, bril- 

 liantly polished ; beaks low, small, the prodissoconch obvious ; hinge narrow, 

 with, in the left valve, a long, narrow posterior lamella, mostly low and feeble, 

 with a small triangular elevated part distally, below this a short resiliary scar 

 near the umbo, and anteriorly two small, short lamellae, one directly under the 

 umbo, the other larger, longer, and more oblique and the hinge-plate in front 

 of it flattish; in the right valve the teeth are similar with the hinge-plate 

 grooved above them ; posterior part of the shell slightly longer, interior faintly 

 radially striated, margins entire. Lon. 11.5, alt. 8.7, diam. 3.8 mm.; a larger 

 fragment was originally about 13 mm. long. 



This species appears to be rare. Its outline is not unlike that of " Monta- 

 cuta" Bowmani Holmes (Post- PI. Fos. S. Car., p. 30), but that shell is de- 

 scribed and figured as having the hinge of Rochefortia. The horizon to which 

 M. Bowmani belongs is not mentioned by Holmes. The present species is 

 named in honor of Mr. W. G. Mazyck, of Charleston, South Carolina. 



" Lepton" longipes Stimpson (Proc. Boston Soc. Nat. Hist., v., p. in, Feb., 

 1855), from South Carolina, is a Bornia so far as the shell is concerned, but 

 the soft parts exhibit characters intermediate between those of Bornia and 

 Lepton. The mantle has not the hood-like prolongation anteriorly which 

 is found in B. corbuloides, though it extends beyond the borders of the shell. 

 There are two long anterior cirrhi and one posterior, dorsally situated, in 

 Stimpson's shell; the foot is very extensile and the posterior portion has a 

 cylindrical extension, distally pointed, from the apex of which a byssal secre- 

 tion may be ejected. For these reasons I have proposed the sectional name 

 of Ceratobornia for this and other species which may eventually prove to have 

 a similar organization.* 



* Proc. U. S. Nat. Mus., xxi., No. 1177, p. 889, pi. 88, figs. 10, 11, 13, 1899. 



