272 PALEONTOLOGY OP NEW JERSEY. 



Jersey; and both Mr. Gabb, iu 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 in a groove of the larger one, as these two 

 feattu'es are all that Mr. Com'ad claims, his generic description being as 

 follows: "Differs from Ptychocerus 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. S. Geol. Survey, vol. 9, p. 410, places Solenoceras as a 

 synonym of Ptychoceras, as he not only questions the deflection or recurv- 

 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 



