168 PSEUDOCERATITES OF THE CRETACEOUS. 
increase in size in last part of the outer volution. The venter runs from 2 
to 7 mm. in width on this one volution. The living chamber is complete 
internally and is somewhat less than one-half of a volution in length. The 
sutures resemble those of specimens described above except that there are 
only seven saddles, the fifth and sixth very broad and bifid, the seventh 
entire. 
The first to third lobes are very slightly digitated; the rest are entire. 
Bohin’s studies of the originals of the descriptions of this species have 
been referred to in the generic description. Whatever doubts of Bohm’s con- 
clusions may remain in the mind, it is surely safer to follow such an investi- 
gator, who has worked over the original materials, than to indulge in 
speculations with regard to the exact meaning of von Buch’s and Roemer’s 
descriptions and figures, about which the most opposite opmions might be 
reasonably entertained. 
ENGONOCERAS SUBJECTUM n. sp. Hyatt. 
Pl. XXI, figs. 2-6; Pl. XXII, figs. 1-5. 
A good cast of this form (No. 431 in Museum of Comparative 
Zoology) is 101 mm. in diameter, the inner oldest part of the outer volution 
being partially destroyed, so that this could not be measured. The living 
chamber was probably, when perfect, not less than one-half of a volution 
in length. The whole diameter was about 102 mm.; the transverse diameter 
was decreased so by compression that the measurement near base of living 
chamber could not be relied on, but this was 18 mm., the ventro-dorsal 
breadth of side being at the same place 43 mm. The living chamber 
having been excavated, it was possible to measure the interior volution in 
the same line with the largest diameter given above. This was found to 
be 73 mm., the largest volution being 40 mm., the umbilicus 7 mm., the 
opposite part of same volution 26 mm. No shell was present on this cast. 
The involution covers up the entire side of inner volution at diameter of 
86 mm. This is found in several specimens, but does not appear to be 
invariable. There are large nodes along the umbilical shoulders, very 
obscure nodose folds along the central surfaces of lateral zones, and 
prominent elongated alternating nodes along either border of the venter. 
These last are finer in the ephebic stage than in the gerontic substages 
At diameter approaching 100 mm. the venter loses the flattened aspect ot 
