64 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
specimen of St. John and Worthen. Twelve teeth are now visible in the 
foremost row on the right-hand side of the Cambridge specimen; 13 
are to be seen in the second row; and of the third row, which has been 
fractured across, and hence ap- 
pears only in section, only 6 
remain. The largest tooth in 
the foremost of the antero- 
lateral series has a length of 
2.1 cm.; the largest in the 
second row, 3cm. Other meas- 
urements that may be con- 
veniently recorded here are as 
follows: A straight line drawn 
from the apex of the posterior 
to the anterior symphysial 
tooth in the Kansas specimen 
measures 20cm.; and a line 
joining the terminal apices of 
the Nebraska specimen has a 
length of 16.5cm. The maxi- 
mum width of the symphysial 
series is 6cm. in the former 
example, and 6.2cm. in the 
latter. The conformation of 
the individual teeth being suffi- 
ciently evident from the fig- 
Fie. 2. 
Campodus variabilis (N. & W.). Missourian ; 
Osage County, Kansas. Generalized cross- 
section of a symphysial tooth. X 3. 
ures and cross-sections, further description here is superfluous. The 
cross-section shown in text-figure 2 is taken through the fourth tooth 
from the front in the Kansan specimen, except that the vertical thickness 
in the median line is estimated from the most anterior tooth, which is 
the only one displaying this dimension. In the Nebraska specimen the 
vasodentine of the roots is largely decomposed. 
Campyloprion. 
(Plate 4.) 
This genus was established for the reception of certain forms occupy- 
ing an intermediate position between Edestus s. s. and Helicoprion. 
The latter genus is known at present only by the type species, H. besson- 
owt Karpinsky, from the Permo-Carboniferous of Russia. Edestus in its 
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