234 PROCEEDINGS OF THE ACADEMY OF 
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. 
ce. The last tooth. 
Fig. 2. Macrocyclis Duranti, Newce. 
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. 
ce. 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. 
6b. Extreme marginals. 
Norre.—This plate must be studied in connection with the descriptions 
in the text. It will there bé seen that Fig. 2a and Fig. 4a are taken from 
below, to better show the base of attachment. Figs. 3a, 5a, and 4c are 
taken from above, and more correctly show the form of the cusp. 
PuaTE II. 
Fig. 1. Zonites levigatus, 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. 
6b. Extreme marginals from two adjacent rows. 
Fig. 5. Zonites inornatus, Say. 
a. Central and first three laterals. 
6. Marginal tooth fourth from the end. 
