172 PSEUDOCERATITES OF THE CRETACEOUS. 
costze between these. This cast, the type of the species, shows no gerontic 
characters at the diameter of 93.5 mm. The greatest transverse diameter is 
at the umbilical shoulders and is 25 mm., the breadth of the side at the 
same point being 50 mm. The sutures are quite different from those speci- 
mens described below, but there is the same general character: the second 
lateral saddle and the fifth are bifid; the sixth is unequally trifid; the seventh 
is a compound saddle with two bifid arms; the eighth to the tenth are entire 
or flat. The more gibbous sides, the prolonged stage during which the 
nodes persist and are sharply defined, and the large number of bifid saddles 
characterize this species. The sutures are the most complex, with exception 
of Eng. roemeri, of any that have been so far descibed in the genus. 
The largest fragment in the National Museum is about three-eighths 
of a volution. Widest diameter is 91 mm.; the distance from line of invo- 
lution to venter is 50 mm. at the larger end and 38 mm. at the smaller end; 
and the transverse diameters are 20 mm. and 16 mm., respectively. This 
specimen was probably entirely uncompressed. The venter is narrow and 
flat and the sides are slightly gibbous and highly convergent outside of the 
middle row of obscure nodes. Between these and the umbilical shoulders, 
however, a flattened zone is developed, which may even slightly slope 
inward The usual row of nodes is present on the umbilical shoulders, 
and also the rows of alternating tubercles on each side of the venter. The 
latter are sharp and well formed, elongated, and sufficiently numerous to 
give a decidedly zigzag aspect to the narrow venter. 
The venter is flat in the early part of the neanic stage and much 
broader in proportion to the volution than in later stages, as it is in most 
species of this genus. The volution has more flattened sides at this age, 
and the involution begins to cover up the volutions to the umbilical 
shoulders even at this early stage. 
The sutures are well separated, as in other shells of this genus, and 
are very remarkable. There are on the right side ten lateral lobes and 
eleven saddles at the larger end of this fragment and the same number at 
the smaller end. These are more difficult to count and quite different on 
the left side. The ventral lobe is symmetrical and of the typical form. 
On the right side the first lateral saddle is bifid, the outer arm short, 
broad, and spreading, the inner also broader than in most other forms; 
the outer is subdivided by a minute marginal or slightly and unequally 
