FOURTH, OR CORONICERAN BRANCH. 187 
outline, and the pile are similar. As a whole these four specimens differ from 
Cor. Sauzeanum, var. Gaudryi, in having a shallower umbilicus and a somewhat 
greater number of whorls in proportion to the size of the shell. One specimen 
from Semur is intermediate in characters between the German specimens, and 
the true Sauzeanum, var. Gaudryi. The Semur specimens also differ in the depth 
and groove-like aspect of the channels, and the almost sunken aspect of the keel 
on the casts. The prominence of the genicule reminds one of the fifth whorl of 
Sauzeanum, var. Gaudryi. 
Both specimens from Semur have similar sutures. The ventral lobe is deep, 
the superior lateral saddles and lobes very shallow and broad, the inferior lateral 
saddles very prominent, and the inferior lateral lobes obtuse. The marginal lobes — 
are more evenly distributed than in the German variety.. The sutures on the 
seventh whorl have an abdominal lobe from one half to two fifths longer than 
the superior lateral lobes, and the inferior lateral saddles exceed the superior 
laterals in the same proportion.. Both in fact approximate to Cor. Sauzeanum, var. 
Gaudryi, by their sutures. In the German specimens the lobes and saddles show 
about the same general proportions, though the inferior lateral saddles are much 
broader, and the inferior lateral lobes deeper, and acute instead of obtuse. There 
is a large specimen in Professor Quenstedt’s collection from Bodelshausen - 
(No. 10673), which is similar to these, but unfortunately the name of this was 
not noted. 
The keel is quite prominent at the earliest period observed on the first 
quarter of the fourth whorl, but the channels are hardly discernible. At this 
period the channel ridges are not developed, and the tuberculated genicule are 
high upon the sides. When the channel ridges are distinguishable on the fifth 
volution, they are continuous. The keel loses its prominence after the channels 
deepen upon the latter part of the fifth, and the early part of the sixth whorl. 
The pile in the young are more numerous than in the adult. © 
The largest specimen from Semur measured 348 mm. in diameter, and had 
about eight and a half volutions. The pile retained all their adult peculiarities 
and original sharpness, and the quadragonal form of the whorl was also un- 
changed. The channels were, however, broader and shallower than in the adult. 
The approximation of this form in aspect and characteristics to its morphological 
equivalent, Cor. lyra, is so close, that only the most careful study can show them 
to have been distinct. ‘The young of these two species are quite different at all 
stages, and can generally be readily separated. 
This species has always the broad abdomen of Sauzeanum and its spinous 
tubercles, and the young are not so stout as in Cor. lyra. In the succeeding 
stages the young of dra rapidly changes from divergent to. parallel sided, and 
then to a convergent sided whorl, whereas in this species the development is 
much slower. The later stages (Plate VII. Fig. 8) are similar in form to lyra 
when quite small (Plate IV. Fig. 9). The genicule usually cut up the channel 
ridges into waves, and, though not invariable in the species, this occurs so gen- 
erally as to be a useful distinction, and is evidently of genetic importance in the 
series. The resemblances of the young to the adult of Aridion and the young of 
