100 CRETACEOUS GASTROPODA 
ce. Sub-family—V OLUTOMITRIN 1. 
(Vide Gray’s Guide, 1857, p. 836; Adams’ Genera, II, p. 619.) 
XX. VOLUTOMITRA, Gray, 1847. 
Gray has separated lately the genus Volutomitra in a sub-family of his Vororma 
on the ground of the middle tooth of the lingual membrane being stronger, with a 
cone-like apex. The shell of Volutomitra itself may he said to have as much resem- 
blance to the vozurm as to the mzrriva, with the former of which it agrees 
generally in the smoothness of the shell or at least the want of any stronger trans- 
verse ribs, while the columellar plaits are arranged more like to those of the 
urrrin&. In so far there appears every reason for supposing, that the differences 
pointed out by Dr. Gray have a classificatory value, and that the sub-family may stand 
as indicating a passage from the vozurrym to the wrrm, in which case there is 
by far less reason to separate the latter sub-family altogether from the Vozuripm. 
The same author says, that the tentacles of 7. Groenlondica are close at the base, 
the eyes one-third above the base (but on large tubercles!) and the siphon simple, 
which evidently agrees much more with other uzrrmv# than with the rozvriva. 
There are several fossil tertiary species, which belong to this group. None of 
the mrrrivm described from eretaceous rocks exhibits, however, the characters 
of the genus, and the species, which we here refer to it, may be said to 
agree only exteriorly with it, as we have not been able to procure a quite perfect 
specimen. 
1. VoLUTOMITRA CANALICULATA, Sfoliczka. Pl. IX, Figs. 12 and 13. 
Vol. testa ovate-elongata ; anfractibus quinis, convexis, prope suturam eanalicula- 
tis, spiraliter numerosissime atque minute-sulcatis, sew striatis: striis in medio ultima 
wnfractus subobsoletis ; apertura angusta, elongata, antice atque postice subacuta ; 
canali lateratiter curvato, prolongato ; labio triplicato, plica antica tenwi, duobus 
posterioribus crassioribus, fere equalibus. 
Spiral angle 60°; sutural angle 10°. 
Height of last whorl : total of shell (considered as 1:00°) ne woe O:63~ 
An ovately elongated shell composed of about five convex volutions, the last 
exceeding the spire in height. Below the suture there is a distinct broad furrow on 
all whorls, the margin of the suture itself being marked by an elevated line, and a 
similar line is distinguished on the last whorl below the furrow, being bounded on 
either side by an impression. All the other surface of the shell is densely covered. 
with fine spiral stris and sulci respectively, both becoming usually obsolete on the 
middle of the last whorl and also partially so on the upper volutions of the spire. 
The aperture is much elongated, being laterally compressed and pointed on each end. 
The canal is produced and bent a little to the left side (in front view), and more so 
than usually in living species of the same genus. There are three folds on the 
inner lip, the two posterior stronger and about equal, the anterior somewhat thinner 
