Dark Is Before the Daivn 361 



have hairs, indications of external ears, tiny teeth in their gums, 

 stumps of hind limbs, and nostrils on the front of their noses, they 

 also display the whole development of the tail just as we have told 

 it, and finally, their dorsal fins first show as a narrow ridge along 

 the crest of their hinder back. Before the saro-like. flanges appear on 

 the sides of their tails, moreover, they are practically indistinguish- 

 able from dogs or even ourselves at certain stages of embryonic de- 

 velopment. They are, in fact, pretty good imitations of the "First 

 Ancestors," in miniature. They sometimes also display another fea- 

 ture that comes as a great surprise. 



Dotted about the embryonic skins of several species may be found 

 strange little coinlike plates of tissue containing bone-building cells. 

 Sometimes these are rectangular in shape and form contiguous 

 checkerboards covering specific areas, notably the top of the head, 

 the sides of the forebody, and the mid-back. The common porpoise 

 is often dotted with scattered bony tubercles set under the skin, and 

 a row of them may line the fore edge of the dorsal fin. The Finless 

 Porpoise (Neomeris phocaenoides), which is found round the coasts 

 of India, has several rows of these tubercles extending along the ridge 

 of its back from behind the head to the tail. They are squarish, set 

 close together, have roughened centers, are developed in the skin, 

 are calcified — that is, are true bone — and are thus morphologically 

 the same as the bony scutes that make up the "shell" of armadillos. 

 Even more significant in this respect is an extinct dolphin knov/n 

 from complete skeletons and named Delphinopsis freyeri. This has 

 whole regions of its body covered by a complete and regularly ar- 

 ranged armature of these little, interlocking, bony scutes. Similar 

 structures have been found in association with the skeletons of some 

 of the Zeuglodonts. 



From this it would appear not only possible but quite likely that 

 the land-living "First Ancestors" of the whales were not just hairy 

 beasts but, rather, specialized types covered with an armor of bony 

 plates, like the armadillos, but with hair about the face, beneath the 

 body, and probably on the limbs. If they were not, the development 

 of such bony scutes and their subsequent loss by all sorts of whales 

 constitutes an even more senseless procedure than the development 

 and loss of hair. 



The strongest argument in favor of a tropical riverine origin for 



