PLATE IV 



BREATHING VALVE AND TEETH OF CHLAMTDOSELACHUS AHGUIHEUS 



Fig. 1 1 . The angular breathing-valve of the 1485'inm. specimen in the collections of the American Museum. 



From a photograph, A. M. N. H. 



Fig. 12. The somewhat rounded breathing'valve of a 1550'mm. specimen in the American Museum. 



Note the very small teeth at the base of the valve. 

 From a photograph, A. M. N. H. 



Fig. 13. The greatly enlarged anterior end of the upper jaw of the specimen from Columbia University. 

 Note the crescentic breathing- valve, and the double row of half-sized teeth near 

 the symphysis of the jaw-cartilages. 

 From a photograph, A. M. N. H. 



Fig. 14. Anterior end of the upper jaw of Doctor White's specimen (see page 253) showing the single row 



of half-sized teeth near the symphysis. 

 From a photograph, A. M. N. H. 



