RESTORATIONS OF DEVONIAN CEPHALOPODS 461 
are only peculiarly distorted individuals of well-marked species. 
The species most distorted is G. wisconsinense, a unique and beauti- 
ful fossil. In this species it appears that the shell was compara- 
tively thin. The peculiar shape of the 
shell probably caused a_ whirling 
motion as the dead animal sank 
through the waters to the soft bottom 
of calcareous mud, where it rested in 
the position it had in the water im- 
mediately before striking the bottom. 
As a result of this whirling motion, it 
was seldom that two individuals struck 
the bottom at precisely the same angle. 
The effect, whether due to impact or 
to the weight of the superimposed 
sediments, was a distortion in different 
planes resulting in a great variety of 
fossil forms. In the case of the other 
species discussed in this paper it 
appears either that the shells were 
stronger, or that they reached the 
bottom with their vertical axis in ap- 9 
proximately a horizontal position. Fic. 2.—A restoration in plaster 
Because of one or both of these con- of Gomphoceras wisconsinense N.S. 
abe ; if The shape of the apex is somewhat 
ditions» «the zouthmes; except im the ) <a acupe 
transverse section, is little changed. 
The outline of the shells, as has been said, is quite well known, 
but the internal structure is poorly preserved. The air-chambers 
are usually preserved, but the position of the siphuncle is, in some 
species, in doubt, and in only one species is the relation between the 
siphuncle and hyponomic sinus shown. 
The impossibility of determining the position of the siphuncle com- 
pels the use of the broader classification used in the older literature. 
Gomphoceras wisconsinense n. sp. 
(Figs. 1, 2, 3) 
Description.—Shell very large, straight, extremely gibbous. Longitudinal 
section like a pointed amphora. Between the last septum and the apex the 
