8o 



THE STERNUM. 



[chap. 



ossifies from three distinct pairs of nuclei, and a large 

 median fontinelle remains between the first and second 



Fig. 37. — Sternum of Cachalot or Sperm Whale (Physctcr macrocephalus), J 4 . 



pair. 1 In the specimen in the Museum of the Royal College 

 of Surgeons, which is very nearly adult, each half of the 



Fig. 38.— Sternum of Greenland Right Whale [Batoua mysticetus), ,',,. 



presternum (ps) has coalesced with the corresponding 

 half of the first segment of the mesosternum (ms 1 ), but the 



1 I have observed this in animals evidently of great age. 



