KNEMICERATID®. 147 
The nodes continue to increase in length and size throughout life until 
in the latter half of the gerontic living chamber, when they show a decided 
and rapid decrease on the venter but persistently increase on the umbilical 
shoulders until near the end of this chamber. The living chamber was 
incomplete on the venter in all of these specimens, although in several it 
was complete near the umbilicus and somewhat over one-fourth of a volution 
in length. 
The first lateral saddles are bifid, having two broad arms, and both of 
these are again faintly bifurcated, these subdivisions -being minutely 
denticulated on the edges in perfectly unworn sutures, which can be found 
best by removing encrusting ostreans. In some specimens the second 
lateral saddle does not split up completely from the first, and instead of 
three principal lateral saddles there are but two, as shown in Pl. XVI, fig. 5. 
In others the division is complete, as it probably is in the later stage of the 
specimen shown in Pl. XVI, fig. 8. No specimen so far seen carries out 
the complete division of the remaining first lateral, although in some the 
median marginal lobe is quite long. It is a curious fact that all of these 
specimens—eleven in number and collected from five different sources— 
should have encrusting bryozoa and ostreans on the exterior of the cast and 
all more or less worn on all other parts of the surface. The lobes and 
saddles nowhere exhibit, and it is not likely that this species ever exhibited, 
the peculiar lobes and saddles figured by von Buch on his pl. 7. The 
entire suture seems to be incorrect for this species, whereas those given 
in pl. 6 are right so far as they go, although taken from the usual 
worn surfaces, of casts. Béhm’s figure, quoted below, is accurate, but 
belongs to an older stage than that figured in this work. The 
second and sixth lateral saddles are bifid, the seventh and eighth broad, 
flattened, and entire. There are marks upon unworn sutures indicating the 
presence of slight denticles on the edges of the principal saddles, but no 
such divisions and prominent marginals as in von Buch’s figure, pl. 7. The 
ventral lobe has two arms as in Engonoceras ; the dividing siphonal saddle is 
apparently flat, but when clearly defined it has a diminishing base divided 
by a minute siphonal lobe. Faint denticulations are present on both this 
saddle and the sides of the arms of the ventral lobe. The lateral lobes are 
club shaped, denticulated on the top, but entire on the sides near their 
base between the phylliform bases of the saddle. There are irregular trifid 
