Proofs of Evolution. 305 



Tmds. Here is a being which eats and grows like an animal 

 and yet is propagated like a vegetable. The sponge is an 

 egg-layer. Its eggs bud or hatch and grow to adult life. 

 These cases among the Protista, Avhich are neither strictly 

 animal or vegetable, s\;ggest the beginning of differentiation 

 from a common protoplasmic cell. 



Turning to the fossil world, we find, as we should expect, 

 innumerable examples of connecting forms. In the later 

 deposits, we find remains of toothed birds, having many 

 reptilian characteristics. Reptiles were then not a fixed 

 type, but shaded gradually from fish to bird. The Archse- 

 opteryx, a fossil rarely found, was a true link between the 

 birds and reptiles. 



Certainly, no two kinds of living things are more unlike 

 than birds and reptiles, or more antagonistic in their 

 natures, mutually preying on each other; and yet their 

 relationship is clearly established. Psychologically, they 

 have nothing in common but hate ; and yet the bird is only 

 a feathered reptile. Within three years, there was found, 

 in the slate deposits of Bavaria, a specimen of a reptilian- 

 bird — now preserved in the P)ritish Museum — which has 

 a long, lizard-like tail of twenty joints. Says Professor 

 Vogt, '' This is neither bird nor reptile, but a decided link 

 between the two." In the later chalk formations many 

 fossils have been found by Prof. Marsh, more bird-like in 

 character, but still possessing teeth. The flying dragons 

 afford another link between birds and reptiles. The front 

 half was decidedly bird-like, but the hind legs and pelvis 

 were strongly reptilian. 



The anaplotherium connects the swine with the cud- 

 chewers ; the zeuglodon connects Avhales with seals ; and the 

 palaeotherium connects hogs with the rliinoceros. These 

 are all true links. 



A remarkable example of a perfect succession of links is 

 found in the fossil shells of the Tertiary rocks of Wurtem- 

 berg, which are literally packed with fossil forms. These 

 shells show a complete grading to correspond with the 

 order of the* rock-deposits. Here is evolutionary ])erfection 

 without a break. The life once within these shells, in its 

 tribal liistory })resents no "missing links." 



To sum up, we find the sponge family — the animal- vege- 

 table — near the original i)roto])lasm. The lancelet — the 

 first of the back-bone tribe, with only a line of cartilage in 



