INSLTIT'TK OF SCIENCE, PHILADELPHIA. 81 



and Holmes as being abundant in the Post-Pliocene deposits of South 

 Carolina, and but barely differing from M. limatida, is undoubtedly the 

 recent M. apicina. 



Oliva literata, Lamarck. 



Annales du Museum, xvi, p. 315. 



Tryon, Manual of Conchology, v, p. 83, pi. 31, figs. 5-7. 



Oliva reticularis, Lamarck. 



Annales du Museum, xvi, p. 314. 



Tryon, Manual of Conchology, v, p. 83, pi. 30, figs. 90-95; pi. 31, figs. 96, 4; 



Pi. 34, fi g- 57- 



Both of these forms, as far as I am able to judge, are represented 

 among the fossils of the Caloosahatchie. The two species, however, so 

 very closely resemble one another in the general characters of the shell, 

 that I am far from certain that they can in all cases be distinguished in 

 the absence of color-markings. The produced and more attenuated 

 spire of 0. literata, which may serve in the majority of instances to 

 separate this species from 0. reticularis, is not a constant distinguishing 

 character, inasmuch as we sometimes find the relative condition of this 

 portion of the shell reversed ; i. c., depressed in 0. literata and elevated 

 in 0. reticularis. A more constant character can, perhaps, be obtained 

 from the direction taken by the basal columellar folds, which, as a 

 rule, are slightly more transverse and arched in 0. reticularis more 

 nearly direct in 0. literata. I must admit, however, that the correspon- 

 dences and divergences seen in these minor characters give but insecure 

 grounds for either the determination or separation of the species ; 

 indeed, it appears to me, it might be fairly questioned whether the two 

 living forms here indicated are not in reality only varieties of one and the 

 same species. 



Columbella rusticoides, nov. sp. Fig. 9*. 



Shell turreted, with an acute spire of some six volutions ; whorls 

 convex, impressed below the suture, the uppermost obscurely plicated, 

 the lower ones indistinctly (longitudinally) lined ; body-whorl high, flat- 

 tened on the shoulder, and ornamented with numerous revolving lines 

 (or bands), the upper of which are nearly obsolete ; aperture ascending, 

 narrow, somewhat more than one-half the length of the shell ; outer lip 

 thick, coarsely crenulated ; columellar surface with five or six basal beads. 



Length, .5 inch. 



From the banks below Fort Thompson. 



This species is very close to the recent (European) C. rustica, differing 

 from it mainly in the upper angulation of the body-whorl and the sub- 

 sutural sulcation of the whorls generally. It is a little remarkable that 

 it should approach a trans-Atlantic form more nearJv than any of the 

 American species. 

 6 



