SPHENODISCID®. 67 
The remaining lobes have one large median saddle and an equal 
number of small lobes as if derived from the bifid type. There is a series 
from a primitive bifid lobe, the eleventh, and only the twelfth lobe is single. 
On the right side the twelfth lobe is on the line of involution, whereas on 
the left side that line is oceupied by a saddle. The lobes are very short 
and broad. 
The first six saddles have broad phylliform bases and the first five are 
bifid on both sides, being equally divided by a small median lobe, the sixth 
is transitional and entire; the remaining saddles are of the same type but so 
short and broad that they appear to be flattened at the base, and in fact are 
approximations to that type. 
The most remarkable fact about this cast is what appears to be the 
living chamber. The evidences of the existence of a perfect living chamber 
on this cast seem undeniable and there is every mark of an aperture with an 
entire reflected lip. And what is still more remarkable, the last four sutures 
on the left side are shortened as if absorbed by pressure after they had 
been built. The fourth has lost the three inner rows of lobes and saddles, 
the third has lost seven, and the eighth saddle is partly gone; the second 
has only four saddles left and faint traces of fifth lateral lobe and outer side 
of the saddle, and the basal septum is represented by hardly perceptible 
traces of first, second, and third lateral saddles, no ventral or any other 
lobes. 
On the right side the pressure of the body has shortened up five of the 
sutures. The fifth has lost all the inner entire saddles and their lobes 
except one-half of the last outer one, the sixth row from the umbilicus and 
the seventh from the venter. The fourth has lost this remaining half and 
part of the next saddle, the third has not been absorbed quite so far 
and has the sixth saddle from the venter and part of the next inner lobe, 
the second has first four lobes and saddles, but only one-half of the suture 
of the fifth saddle. The tracings of the sutures of the basal septum are 
slighter than on the other side and includes as on that side only the faintest 
possible traces of the bases of the first three saddles. The interval between 
the fifth suture on the right side, the last perfect one, and the apparent 
aperture on the line of involution is only 6 mm. ‘The interval between 
the same and the half absorbed sixth saddle (from the venter) of the 
second suture is only 4 mm. The rostrum of the aperture is incomplete, 
