272 PALEONTOLOGY OF NEW JERSEY. 
Jersey; and both Mr. Gabb, in his Synopsis, and Mr. Meek, in his Check 
List, follow him in citing it from both States. Mr. Gabb, although admitting 
the genus as a valid one, is inclined to dispute the deflection of the outer 
part of the tube. This would leave the genus to stand entirely upon the 
feature of the smaller tube lying ina groove of the larger one, as these two 
features are all that Mr. Conrad claims, his generic description being as 
follows: ‘Differs from Prycnocerus D’Orbigny, in the smaller tube lying 
in a furrow of the larger one, which is straight only for a short distance 
from the junction, and then suddenly recurved. Mr. Meek in his Invert. 
Paleont. of the U. 8. Geol. Survey, vol. 9, p. 410, places Solenoceras as a 
synonym of Ptychoceras, as he not only questions the deflection or recury- 
ing of the shell a second time, but objects to the enfolding of the smaller 
tube within a groove in the larger one being considered as of generic im- 
portance. On examining Dr. Morton’s specimen I think there is every 
evidence that can be derived from an internal cast of such a shell that the 
supposed deflection of the tube at.the outer end of the fragment is only 
the thickening and rounding out of the completed or adult aperture of the 
shell, as the cast of the opening has been contracted on all sides and made 
to form a completely circular aperture or opening. From the specimen known 
there is no evidence as to what form the earlier parts of the shell may have 
had, other than that it was most probably elliptical or slightly flattened in 
a transverse section and also very slightly bent longitudinally; but beyond 
the length of the fragment, which is only seven-eighths of an inch, there is 
no evidence whatever afforded, and I have never known of any other indi- 
vidual being seen, all references being made to this one individual. 
While working over the Cretaceous fossils from the Black Hills of 
Dakota, published in Capt. Jenny’s report of the Black Hills expedition, I 
found examples of shells having characters very much like the one from 
New Jersey, but not so finely annulated, in which the earlier portion of the 
shell was bent and curved in such a manner that, had the larger part of the 
tube been continued beyond about the same length as the same part of this 
New Jersey specimen, it would of necessity have been compelled to become 
deflected in precisely the direction and manner in which Mr. Conrad sup- 
posed that one to have been in order to have grown beyond that point. 
Beyond this I have very good reason to suppose that the embryonic portion 
