Lect. IL] all animals COME FKOM EGGS. 49 



2. The second character is the presence of the old familiar egg- 

 breaker on the bend of the " neb " above, just like that seen in the 

 chick of any bird, and in the embryos of the Turtles, Tortoises, 

 Crocodiles, and Alligators. 



So that we may accuse the Duck-billed Platypus, and say — " You 

 wore hatched out of an egg and are not a proper mammal at all." 

 But if he, like the Lamb, asserts his innocence, then we, hke the 

 Wolf, will throw the accusation backwards, and say — " Your father 

 (ancestor) was so produced, and you are, after aU, merely an oviparous 

 creature." Probably the highest dignity this creature wiU ever attain 

 to in Biology will be to be classified as an Ovoviviparous type, a 

 sort of compromise between a Eeptile and a Mammal. That may be 

 true, for all animals come from eggs, — omne animal ex ovo, — and as 

 Man is known to be an animal, he also once had all his potential 

 excellences squeezed into the small space of an egg-shell — an egg 

 which was small, indeed. We hope soon to get more light upon 

 the development of the Prototheria. Some hunters belonging to 

 the last and best kinds of the Eutheria are upon their track, and 

 they must hide themselves either in the earth beneath, or in the waters 

 under the earth, if they would escape them. It is, I think, more 

 than probable that the original Prototherians possessed teeth; yet 

 these may have been, and most probably were, of a stiU simpler 

 type than those of Opossums and Kangaroos, from whose teeth we 

 start in making an ascending survey of these organs in the Manmaalia. 

 It is not unreasonable to think that the mammals wliich have degene- 

 rate teeth, such as Sloths, Armadillos, the Aard-Vark, might serve to 

 give us some idea of what this primitive Mammalian dentition was 

 like. Anyhow, if they had a good mouthful of teeth, their ujjper 

 and lower jaws did not resemble those of their highly modified descend- 

 ants ; probably they were very much like what we see in the least 

 specialised of the living Marsupials, namely, in the Opossums of the 

 Western World. As to their outer covering, of course they all were 

 more or less clothed with a hairy garment, for this is correlated, always, 

 with milk-glands ; when, " in the end of the days," the last mammal 

 appears, but appears shorn of that covering, it has to be borrowed, 

 again, from those types in which it had not been suppressed. "Unto 

 Adam also, and to his wife, did the Lord God make coats of skins, and 

 clothed them.'' This has become, as everyone knows, a custom among 



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