114 ON A SKELETON OF A WHALE IN THE 



As we have them, the changes may be in some measure 

 noted by a study of the bodies which increase in size to the 

 fourth of the series, ,and then suddenly decrease. There are 

 evidently several vertebrae missing between the third and fourth 

 vertebrae, plate II. 



In the third the body is larger than in any other of the whole 

 series. Here also the spine has an entirely different form from 

 that found in the preceding bones. It is not only shorter, and 

 relatively broader, but, as may be seen in plates II and IV, there 

 are short, blunt metapophyses. The centrum here has a height 

 of 87mm. (3^ inches), a width of 83mm. (3J inches), and a 

 length of 95mm. (3f inches). The neural canal, however, is 

 reduced to a width of only 10mm., or a seventh of that in the 

 first vertebra mentioned. The transverse processes are also 

 reduced to mere ridges, and they soon grow so small as to be 

 hardly noticeable, and in the last have nearly disappeared. 



As seen, though not as distinctly as might be desired, there 

 is a backward projection from the spine in h so that the whole 

 ridge, rather than process, is as long as the body. In the caudal 

 last on plate IV, the body is nearly circular. None of the button 

 or discoid vertebrae, such as always form the final portion of the 

 tail, are present. Apparently, there should be at least twelve 

 after the last shown in plate II. The caudal that was acciden- 

 tally left out when the bones were photographed as seen in plate 

 II, is seen in the last plate IV. 



As stated, there were probably twenty-six caudals origin- 

 ally. If twelve of the eighteen missing bones should come 

 after the last in plate II, then six should be placed between the 

 third and fourth of the last series in plate II, or at any rate in 

 that region. 



Chevrons. ~No chevrons were with the bones received from 

 the Halifax museum. In the plate of -the skeleton of Mono- 

 don, Van Benedea and Gervais (Osteograpliie des Cetaces) 

 there are fourteen chevrons. 



