il teeersineer- ltetae 
THIRD, OR VERMICERAN BRANCH. 149 
One specimen in the Museum of Comparative Zodlogy has somewhat deeper 
channels than is usual in this species, but is otherwise quite similar to the raricos- 
tatus-like variety (Plate I. Fig. 19, 20). Quenstedt identifies this variety with 
Arn. kridioides (kridion) in his “ Ammoniten der Schwabischen Jura,” but from 
this species it differs essentially, if we are right in our selection of the form to 
which the name Amm. kridion, Oppel, has been applied. Undoubtedly there is a 
close resemblance between this species and raricostatum, on the one hand, and Arn. 
kridioides on the other. The young and the channels separate it from the former, 
and the great breadth of the whorls, channels, caloceran pile, and sutures, from 
the latter. The raricostatus-like form of the whorl and pile, and absence of 
tubercles, distinguish it from what we consider to be the true fridion. Zieten’s 
figure of a specimen from Kalthenthal, near Stuttgardt, has exactly the aspect 
of this species, and though the abdomen looks somewhat broader in Zieten’s sec- 
tion the pile have no tubercles. It is more like this species than any form of 
kridion or kridioides, if the figure is accurate. 
Caloceras laqueoides, Hyarr. 
Amm. sinemuriense, FRAAS. 
In this specimen, now in the collection of the Museum at Stuttgardt, found, 
according to Fraas, in the Angulatus bed, there is a most singular mingling 
of the characteristics of dagueum with the peculiar pile of Coroniceras Buckland, 
var. sinemuriense. : 
The young and adult whorls are smaller and more numerous than those of 
sinemuriense, and like those of daqueum. The abdomen, however, has narrow 
channels, and many of the pile in the adult have large tubercles somewhat 
thrown back, which give them the aspect of the undivided pile of senemuriense. 
Between these there are usually two or more of the linear pil of one variety of 
laqueum, and the tubercles when covered by the shell do not extend into spines, 
but remain mere tubercles. 
In old age or on the. last whorl of this specimen, which may perhaps be 
prematurely old, the intermediate pilx alone are found, the stout tuberculated 
simuriense-like pile having become obsolescent. At this time the form and 
characteristics of the whorl are precisely as in daqgueum, except the channels; 
these still remain very much shallower. Upon the whole, therefore, it is prob- 
able that this may be a distinct species. Together with others, it shows that 
Caloceras may have forms which are the morphological equivalents of the tuber- 
culated, keeled, and channelled progressive forms of Vermiceras, Coroniceras, 
and Asteroceras. 
