66 WHALES 



Figure 28. Reconstructed skeleton of snake-shaped Basilosaurus cetoides {Owen) which 



lived some j§ million years ago, in what is now Alabama, and was then the sea. The 



skeleton is in the U.S. National Aluseutn in Washington. {Kellogg, igjS.) 



some 25 million years ago. Some of its members were snake-shaped, while 

 others had the torpedo shape so characteristic of modern whales (Fig. 29). 

 From the different characteristics of their skeletons, it would appear that 

 all of them had horizontal flukes which, however, were less pronounced 

 than those of the more recent species. Their necks were fairly short even 

 then, but they still consisted of seven independent vertebrae. The fore- 

 limbs were short and fin-shaped, though they were probably still movable 

 at the elbow, whereas the ulna and radius of the modern Cetaceans are 

 rigidly attached to the humerus. 



As we might have expected, Archaeocetes had a more pronounced 

 pelvic girdle than the extant species, even though it was no longer 

 attached to the vertebral column (Fig. 30). The pelvic bones were much 

 broader and the three components which make up the ossa innominata of 

 the pelvis of terrestrial mammals: ilium, ischium, and pubis, were clearly 

 distinct, and so was the innominate foi'amen. The most striking fact, 

 however, was the presence of a distinct ball and socket joint whereby the 

 femur articulated with the pelvis. The femur was well developed, and 

 though no traces of a tibia were discovered, it is quite possible that 

 vestiges of it existed in the living animal. In any case, all the bones were 

 so small that we may safely assume that the animals showed few, if any, 

 signs of an external fin - at most a small bump. 



All these characteristics make it clear that the Archaeocetes, which 

 became extinct some 25 million years ago, were structurally much more 

 like terrestrial mammals than are modern Cetaceans. We may take this 

 fact as additional proof that the original ancestors of our whales lived on 

 land and that they were built just like all other terrestrial mammals. 



This assumption is borne out further by another characteristic of the 

 Archaeocetes, viz. the position of their nostrils. In the horse, the dog, and 

 all other terrestrial mammals, the nostrils are at the tip of the snout. 

 However, if we examine a whale on the deck of our factory ship, or a dead 

 porpoise on the beach, we shall find that the nostrils, i.e. the blowholes, 



