74 MAMMALIAN DESCEXT. [Lect. HI. 



attain to its present heigiit. And the types that have 

 gone beyond the Metatheria are not the children or 

 descendants of any existing Metatheria. The parents 

 of the lowest Eutheria have been quietly inhumed for 

 many an age, and there is indeed no reason to suppose 

 that they all utilised the Metatherian or pouch-bearing 

 stage at all ; but it is probable that they shot past the 

 Marsupials in an embryonic stage. Many things seen in 

 the Marsupials seem to suggest this ; they have formed 

 for themselves a sort of '' bye-path meadow," far out of 

 the line of the great highway of life. 



Letting imagination fold her wings for a while, we 

 will now look at a very few dry anatomical facts. 



Character 1. — In Bony Fishes, but not in the more 

 archaic Ganoids, there is a median vomer. In the 

 lower Ganoids, e.g., the Sturgeon and Paddle-fish, there 

 is a crop of such bones, with a tendency to a quincuncial 

 arrangement, that is, Avith a middle series, and a row, 

 right and left, opposite the inters23aces of the single 

 row. 



Then, in the Amphibia, and in Snakes, Lizards, and 

 Crocodiles amongst the Eeptiles, there is a pair of 

 vomerine bones, but only in the Chelonians (Turtles, 

 and Tortoises) is there a single median bone. 



In Birds also, certain groups show a single bone, as 

 in rapacious Birds, Fowls, Geese, &c., in other kinds 

 there are two, either for a time, as in Finches, or perma- 

 nently as in Woodpeckers. But the vomer and the 



