TOOTHED WHALES 177 



until it comes to arise from the centrum instead of 

 from the neural arch. 



Kogia belongs to the same division as Physeter. 

 But there are apparent differences between the two 

 whales in the fact now under consideration. The 

 first rib has only the tubercular attachment ; the next 

 eight have the double articulation of Kogia, but the 

 capitular head in the latter ribs of the series is partly 

 inter-centralit articulates with both centra, the one 

 that bears its tuberculum and the one behind. 



In the case of the ninth dorsal vertebra the facet 

 upon the centrum is raised ; in the tenth it is more 

 prominent, and the transverse process to which the 

 tuberculum should be attached has become rudimentary 

 and joins the raised facet already mentioned, but not 

 so as to receive any part of the rib which thus 

 articulates only with the centrum. In the last rib 

 the tubercular process has entirely disappeared and 

 the capitular head of the now one-headed rib is alone 

 left. 



The difference between Physeter and Kogia seems 

 to be great, and as a consequence between Physeter 

 and the dolphins. But the very interesting conditions 

 which Sir William Flower has described in Inia 

 bridge over the apparent gap, and, as I shall attempt 

 to show presently, so does Kogia. In Inia the first 

 seven ribs have the usual two attachments, but the 

 capitular head, at first inter-central, comes to be upon 

 the same vertebra as that which bears the tubercular 

 head. Moreover, the facet upon the centrum becomes 

 raised. The two articular facets upon the eighth 



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