158 PROCEEDINGS OF THE ACADEMY OF 
above, gives a better illustration of this central tooth than is 
shown in my plate. I have lately verified it in fine specimens col- 
lected by myself in Florida. 
In illustrating the dentition of this genus, I have given fig. 1, 
copied from Dr. Leidy’s figure in Terr. Moll. U.S., to show the 
general arrangement en chevron of the rows of teeth. Fig. 2 by 
Morse, copied from L. and Frw. Sh. N. A., I., gives one-half of 
one transverse row of teeth, with the central tooth. Fig. 1 of my 
plate is intended to show the shape of the individual teeth: a gives 
the central with adjacent marginals; 6, the twentieth marginal in 
profile; ce, the thirty-second and last marginal. 
I have not had an opportunity of examining the lingual mem- 
brane of G. bullata, Texasiana, decussata, or Vanuxemensis. 
B. Jaw present. 
Family HELICID. 
This family may be divided by the character of its jaw in con- 
nection with that of its dentition into several subfamilies, V7tr7- 
nine, Helicine, Orthalicine, Succinine. The characteristic of 
each will be given below. 
a. Jaw in one single piece; marginal teeth aculeate. V1ITRININA. 
Genus MACROCYCLIS, Beck. 
Jaw crescentic, ends sharply pointed, anterior surface striated ; 
cutting margin smooth, with a median projection. I have exam- 
ined the jaw of M. Vancouverensis (see fig. 3, 
copied from L. and Frw. Sh., [.), concava, Du- 
ranti, Voyana, and in the West Indian species, 
M. Baudoni,' Petit, and IW. euspira, Pfr. 
Jaw of Macrocyclis ° 
Van COuvorcnaie The general arrangement of the lingual mem- 
brane of Macrocyclis is the same as I have de- 
scribed above for Glandina. 
There are 32 rows in one lingual examined of IZ. Vancowveren- 
sis. The rows of teeth are arranged en chevron. Each row is 
1 See Am. Journ. Conch. VII. 175; Ann. Nat. Hist. N. Y.; X. 305. 
