214 
AUG. F. FOERSTE 
nearly circular, slightly depressed. In one specimen, (fig. 4), 
the dorso-ventral diameter equals 22 mm. and the lateral diameter 
23 mm., the diameter of the siphuncle being 11 mm. The num- 
ber of camerae in a length equal to the diameter of the conch is 
4. The sutures of the septa are directly transverse, curving 
downward slightly along the median part of the ventral side and 
sometimes also laterally. As far as known, the septal necks 
extend downward the length of one camera, and invaginate into 
the top of the septal neck next beneath. 
In the second of the specimens from Multona brook (PI. 24, 
Fig. 3), the siphuncle is in contact with the ventral wall of the 
conch, and is fiattened and not annulated along this line of con- 
tact. Around the remainder of its circumference the siphuncle 
is strongly annulated, in an oblique direction, the annulations 
forming an angle of 70° with the vertical axis of the conch. 
Toward the tip of the endocone the angle made by the annula- 
tions appears to become a little more acute. 
The interior of the rapidly contracting part of the endocone 
and the adjacent part of the cylindrical siphuncle, immediately 
above, is lined by a calcareous deposit. In the Poland specimen 
(PI. 24, Fig. 5), this calcareous deposit fills the lower part of the 
endocone for a distance of 7 mm. from its tip. Immediately above 
this level the thickness of the calcareous deposit equals 2 mm. 
At the upper end of the inversely conical part of the endocone, 
the thickness of the calcareous deposit is 1 to 1.5 mm. Four 
camerae farther up, within the cylindrical part of the endocone, 
the thickness of the calcareous deposit is reduced to half a 
millimeter. 
Two of the specimens from Multona brook preserve casts of 
the interior of the endocone; one of these is figured here (PI. 24, 
Fig. 3). It has proved impossible so far to determine with con- 
fidence how much of the conch is to be included in the structure 
here called the endocone. The conspicuous part of the endocone, 
which tapers rapidly downward, varies from 4 to 6 camerae in 
length in different specimens, but it is not known how much of the 
overlying cylindrical part is to be included in the endocone. In 
other words, it has been impossible, so far, to distinguish be- 
tween the walls of the siphuncle and the walls of the endocone, or 
to determine at what level the top of the cylindrical portion of 
the endocone originates. Possibly all of the cylindrical portion 
