68 



bulletin: museum of comparative zoology. 



allowance for wear, it will still be observed that the coronal apices differ 

 from those of Helicopriou in that they are more obtuse, more coarsely 

 serrated, and the posterior margin is not more steeply inclined than the 

 anterior {cf. 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 



Fig. 4. 



Campyloprion annectans Eastm. 

 Transverse section. X x'cj- 



Fig. 5. 



Helicoprion bessonowi Karp. 

 Transverse section. X f. 



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 3 cm. 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 



