8i6 CRETACEOUS PALEONTOLOGY. 



lion of the septum and i l /\. inches on the outer side. Inner por- 

 tion of the septal line moderately arched forward between the 

 umbilical line and the septal process (or lateral lobe) and reach- 

 ing slightly in advance of the outer division, which from the base 

 of the process or lobe extends almost directly across the back 

 of the shell ; siphon rather large, measuring more than a quarter 

 of an inch in diameter at the outer chamber, cylindrical as far 

 as can be seen; situated at about one-fifth or a little more than 

 one-fifth of the distance from the margin of the inclosed volution 

 to the back of the shell from the inner edge. Prof. Cope states 

 at the edge of the inner fourth. 



The shell substance, some of which remains on the inside of 

 the cast and between two of the chambers, has been very thick, 

 more than a sixteenth of an inch, and presents an imperfect 

 columnar or prismatic structure on the edge. The sides of the 

 cast also show it to have been very heavy where the septa have 

 joined the outer shell, as the cast shows the ridges and chamfer- 

 ing of the edges when the shell has been removed. Some of the 

 cavities left between the filling of chambers also are nearly or 

 quite a line in thickness. Longitudinal lines also mark the cast, 

 showing evidence of muscular attachment along the sides of the 

 chambers between the umbilical cavity and the septal processes 

 or lateral lobes of the septa." (Whitfield.) 



Remarks. This species has not been met with in the recent 

 collections of the Survey. It is possible that it may be identical 

 with Nautilus orbiculatws Tuomey, from Alabama, which was 

 used by Conrad as the type of his genus Hercoglossa*, but the 

 original description of the southern species is so meagre that 

 it is not possible to determine its characters certainly, in the 

 absence of the type, whose whereabouts is unknown. 



Formation and locality. Hornerstown marl, Glassboro 

 (Cope), Vincentown (Whitfield). 



Geographic distribution. New Jersey. 



1 Proc. Acad. Nat. Sci. Phil., vol. 7, (1845), p. 167. 



