302 TRANSACTIONS OF THE WAGNER FREE 



Meioceras eocenense (Meyer). 



Bovicornu eocenense Meyer, Ala. Geol. Rep., p. 79, pi. 3, fig. 12, 1886 ; Red Bluff, Miss. 

 Bovicormi gracile Meyer, Bar. Senck. Nat. Ges. 1887, p. 9, pi. ii. f. 17 ; Jackson, Miss. 

 ? Styliola corptdenta Meyer, Bar. Senck. Nat. Gas. 1887, p. 9, pi. ii. f. 16 ; Jackson, Miss. 



Upper Eocene of Mississippi, Meyer and Aldrich. 



There may be three and probably are two species indicated here, but they 

 cannot be defined until the adult forms are known. At present all that is in- 

 dicated by Meyer's data is that the genus Meioceras exists in the Upper 

 Eocene of Mississippi. I have not seen Meyer's type of Styliola corpiileiita, 

 but the form and size point toward Meioceras, and I have very little doubt that 

 it should be referred there. 



Meioceras nitidum Stimpson. 



Ccecum nitidum Stm., Proc. Best. See. Nat. Hist. iv. p. 112, 1S51. 

 Meioceras nitidum Cpr., P. Z. S. 1858, p. 26. 



Pliocene of the Caloosahatchie, Dall ; Post-Pliocene of Barbados, Cpr. ; 

 living from Tampa Bay, West Florida, to Jamaica, West Indies. 

 This was obtained both adult and in the " Bovicormi " stage. 



Meioceras cingulatum n. s. 

 Plate 16, figures 6, 7. 



Pliocene of the Caloosahatchie and Shell Creek, Florida, Dall and 

 Willcox. 



Shell small, polished, sculptured only with incremental lines ; back 

 strongly arched ; equator tumidly girdled, posterior extremity attenuated ; 

 anterior extreme larger, with the aperture much depressed; plug conical, mu- 

 cro somewhat dorsally situated. Lon. of shell 2.25 ; diam. of anterior end 

 0.5 ; of posterior end 0.3 mm. 



There is quite a range of variation in this species, in regard to the limits 

 of the tumid zone. In many, as in the one which has been figured, it gradu- 

 ally merges in the rest of the surface. In other specimens it is sharply limited 

 and has the appearance of a thick belt around the shell. In many specimens 

 the mucro of the plug projects farther from the posterior aperture, and forms 

 an obtusely rounded cone merging into the surface of the plug without 

 specific limits. 



Family VERMETID^. 

 This group is not very well represented in the American Tertiary. 

 Since the character of the operculum, upon which the group is divided in the 

 recent species, is not available in the case of the fossil forms, we can only 

 approximate to the genus in many cases. For practical purposes our species 

 may be divided into the following groups : 



