﻿5C6 



ures or lobes to correspond with the ventral channels, but these 

 were very indistinct through the shell. 



The siphuncle is of medium size and ventro-centren in the 

 middle of the volution actually seen, and at its termination in what 

 seemed to be the septal floor it was centren. 



The original specimen is a nearly completed whorl, 36 or 37 mm. 

 in diameter, and if prolonged and restored to a point opposite the 

 dorsal marks described above it must have been, when complete, 

 about 74 or 75 mm. in diameter. 



The dark blue color of the last septum of the fragment described 

 indicated that it might have been the floor of the living chamber, 

 and if so, that living chamber must have been over three-quarters 

 of a volution in length. Every observer, however, knows that this 

 inference is open to great doubt because of the frequent invasion 

 of the matrix into septal chambers through accidental breaks in the 

 shells. Pseudo-septa were observed in this specimen. So far as 

 could be seen the involution simply covered the abdomen, and the 

 contact furrow, although not perceptible on the first part of the 

 whorl described, was evidently present later. This is very inter- 

 esting, because this furrow is not persistent upon the uncoiled 

 whorls in any species or form of Lituites yet described and seems 

 to have no hold at all upon the organization. 



Lituites. 



This generic name has been applied to the majority of forms that 

 have the last part of the last whorl or the living chamber free. 

 This general application of the name is so erroneous that it hardly 

 needs discussion. It is, as stated above in this paper, a common 

 tendency of the growth of the whorls in degenerative shells of the 

 Nautiloids throughout the Paleozoic and of the similar forms of 

 Ammonoids during each geologic period, and also a common ten- 

 dency of the extreme senile or paragerontic substage in the ontogeny 

 of all shells of both orders whenever they attain the extreme limits 

 of their existence. Later authors, especially Remele, Notling, 

 Dewitz and Holm, have recognized this fact in some way, either 

 directly or by limiting the generic application of the name Lituites, 

 or by separating the genera Ancistroceras, etc., from Lituites. 

 Remele was the first to demonstrate the divisibility of the Lituitidae 

 into different genera, Boll's previous effort in this direction being 

 unsystematic and subsequently repudiated by himself. 



