68 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
allowance for wear, it will still be observed that the coronal apices differ 
from those of Helicoprion in that they are more obtuse, more coarsely 
serrated, and the posterior margin is not more steeply inclined than the 
anterior (ef. Karpinsky’s text-figure no. 66). A line passing through 
the apex of a given tooth and dividing the crown into halves will inter- 
sect the base of the second tooth behind. , Such a line dropped from the 
apex of the seventh tooth from the distal end, which happens at the 
Fie. 4. Fig. 5. 
Campyloprion annectans EKastm. Helicoprion bessonowi Karp. 
Transverse section. X 75. Transverse section. X #4. 
same time to be the largest to the point of intersection, measures 8 cm. 
It is along this line that the cross-section given in text-figure 4 is taken, 
where the total height is 9.5 cm, and the maximum width 3cm. The 
extreme length of the specimen, measured in a straight line from end to 
end, is 23 cm. 
Reference has already been made to the series of protuberances flank- 
ing the lower extremities of the principal teeth. That these are of the 
same nature as dental structures is obvious, and the corresponding bodies 
ee eee 
