COTLOPOCERATID 2. 95 
secondary lateral saddles, although the deep division and length of the 
immer branch of the first laterals make apparently three saddles. The outer 
branch of the first lateral saddles is narrow, long, much cut up by marginal 
lobes, bifid, and has phylliform elongated marginal saddles. They slightly 
overlap the branches of the ventral lobe, except in the two sutures figured. 
A large marginal springs from their orad parts inward, forming a narrow 
saddle with phylliform single base, undivided on the younger parts of the 
volution and beginning to have a small lobe on outer side in older parts 
of same. These are much longer than in colleti, are attenuated and cut 
into by marginal lobes, and would usually be counted as the second laterals. 
They do not reach to the next sutures and are separated by bare spaces 
from the outlines of the second lateral lobes. The pointed aspect of the 
marginals is noted in PI. X, fig. 4, but the shghtest abrasion would obliterate 
such marks and make all the marginals appear to be rounded, as they did 
to me at first. 
The second laterals are nearly all on a level with these inner branches 
of the first and have solid elongated bases, which are cut into only by 
small pointed marginal lobes and consequently subphylliform, but apicad of 
these there are on each saddle two projecting phylliform branches. The 
third laterals, first auxiliaries, are fully one-third longer than the second 
and broad and solid throughout; the apical openings are not contracted, 
their marginal saddles and lobes being small and short. The extraordinary 
length of these saddles causes them to overlap the inner outlines of the 
third lateral lobe so much that one is apt, unless aware of this, to confuse 
two sutures and consider this saddle short and broad. The remaining 
saddles decrease in length to the umbilicus. The fourth are like the 
third in aspect; the fifth are slender, phylliform, and bifid; the sixth are 
slender, single, and phylliform; the seventh less elongated, less slender, but 
phylliform, and near the umbilical shoulders. On the umbilical zone there 
are two rows of saddles visible on the last part of the outer volution, having 
still the rounded phylliform bases of the Sphenodiscus type. ‘The siphonal 
saddles are quite distinct, larger and more prominent and unlike those of 
any other allied species. 
The ventral lobe is similar to that of Sphenodiscus lenticularis, but has 
spreading trifid arms. The first and second lateral lobes are narrow. The 
first is decidedly bifid, the second is but a shade longer than the first, and 
