NATURAL SCIENCES OF PHILADELPHIA. 157 
since been detected in Gl. truncata,’ rosea, algira,*? Sowerbyana,! 
plicatula, fusiformis,® Albersi ;7 in semitarum,® Phillips? of the 
subgenus Varicella; also solidula” of subgenus Oleacina. This 
central tooth is rather difficult to study, being on a different plane 
than the other teeth, and apparently much less developed. Its 
cusp is generally simple, long, and narrow; but in G. rosea it has 
a decided blunt cutting point, and in G. semitarum it has a long, 
slender, cutting point. 
The side teeth are all of the purely aculeate type; the base of 
attachment is long, narrow, ineurved at sides, gradually rounded 
above, expanded and bluntly truncated below, the general out- 
line being somewhat like that of the sole of a shoe. From this 
base of attachment springs a large aculeate cusp. These side 
teeth are like the marginals in Zonztes, Limaz, ete.; they may 
therefore be called marginal teeth, and the lateral teeth, usually 
present in the Vitrinine, may be said to be entirely wanting. 
As stated above, the marginal teeth increase rapidly in size for 
a short distance from the median line, and then gradually de- 
crease in size, as they pass off laterally, the last tooth being still 
smaller than the first. 
Glandina truncata has 32--l1—32 teeth in each row. I have 
shown in plate I., fig. la, the central and first three marginals ; 
5 is the twentieth marginal; c, the last tooth. Fig. @ and ¢ show 
the teeth as seen from below, thus giving a perfect view of the 
bases of attachment. Fig.b isa strictly profile view. The eighth 
tooth seems to be the largest. The central tooth I find great dif- 
ficulty in studying. It appears to have a simple, long, slender 
base of attachment, truncated above and below with slightly ex- 
panded lateral angles. The sides are somewhat incurved, giving 
the tooth the appearance of a simple modification of the base of 
attachment of the marginals. The figure (2) by Morse, copied 
1 See L. and Frw. Shells, I., fig. 6. 
2 Amer. Journ. Conch., V. 202, fig. 1. 
3 Fischer and Crosse, J. de C. XVI. 234, 1868; Moll. Mex. et Guat., pl. 
IV. fig. 10. 
4 Same, Moll. Mex. et Guat. 73, pl. IV. figs. 6-9. 
5 Same, p. 73. 6 Same, p. 73. 
7 L. and Frw. Shells, I., fig. 10, p. 19. 
8 Proc. A. N. S. Phil. 1874, 49. 9 Same. 
® Ann. Lyc. N. H. of N. Y., X. 347. 
