234 PROCEEDINGS OP THE ACADEMY OP 



The species of the genus foreign to the United States hitherto 

 examined agree in their jaw and lingual dentition with V. 

 Floridana. 



EXPLANATION OF THE PLATES. 

 Plate I. 



Fig. 1. Glandina truncata, Say. 



a. Central and adjacent marginals. 



b. The twentieth tooth. 



c. The last tooth. 



Fig. 2. Macrocyclis Duranti, Newc. 



a. Central and adjacent teeth. 



b. The last two teeth. 

 Fig. 3. M. concava, Say. 



a. Central and adjacent teeth. 



b. The last ten teeth. 



c. The last tooth from another part of the membrane. 

 Fig. 4. M. Vancouverensis, Lea. 



a. Central and adjacent teeth. 



b. The last five teeth. 



c. The first lateral seen from above on a different scale 



of enlargement. 

 Fig. 5. M. Voyana, Newc. 



a. Central and adjacent teeth. 



b. Extreme marginals. 



Note. This plate must be studied in connection with the descriptions 

 in the text. It will there be seen that Fig. 2a and Fig. 4 are taken from 

 below, to better show the base of attachment. Figs. 3a, 5a, and Ac are 

 taken from above, and more correctly show the form of the cusp. 



Plate II. 



Fig. 1. Zonites laevigatas, Pfr. The central tooth with all the 



teeth to the right of it. 

 Fig. 2. The same, more highly enlarged, to the fifth tooth. 

 Fig. 3. Zonites cellarius, Mull. Same reference as in fig. 1. 

 Fig. 4. Zonites friabilis, W. G. B. 



a. Central and adjacent lateral. 



b. Extreme marginals from two adjacent rows. 

 Fig. 5. Zonites inornatus, Say. 



a. Central and first three laterals. 



b. Marginal tooth fourth from the end. 



