Intermediate Types 87 



specimens in a linear series, from the simplest to the 

 most complex, and declared that the arrangement was 

 a representation of the family tree. The fact that the 

 line of descent apparently could have followed along 

 the direction they suggested they were inclined to take 

 as evidence that it had so followed. Huxle}" made the 

 most careful distinction between what he called inter- 

 mediate types and types with a right to be placed in 

 linear order. 



" Every fossil which takes au intermediate place between 

 forms of life already known may be said, so far as it is inter- 

 mediate, to be evidence in favour of evolution, inasnmch as it 

 shews a possible road by which evolution may have taken 

 place. But the mere discovery of such a form does not, in 

 itself, prove that evolution took place by and through it, nor 

 does it constitute more than a presumptive evidence in favour 

 of evolution in general." " The fact that Anoplot/ieridcv ?LTe 

 intermediate between pigs and ruminants does not tell us 

 whether the ruminants have come from the pigs or the pigs 

 from the ruminants, or both from Anoplotheridce, or whether 

 pigs, ruminants, and Anoplotheridce alike may not have 

 diverged from some common stock." 



A familiar instance will make the point at issue plain. 

 Everyone knows that in many respects, in the structure 

 of the skeleton, and the curve of the backbone, and in 

 the development of the brain, the man-like monkeys, 

 the gorilla and its allies, are intermediate between 

 man and the lower monkeys. In the early days of evo- 

 lution it was assumed frequently that the gorilla, etc., 

 were therefore to be regarded as ancestors of man, and 

 they appear as such in more than one well-known 

 treatise on evolutionary biology. We now know that 

 it is exceedingl}^ probable that the gorilla and its allies, 

 although truly intermediate types, and truly shewing 

 a possible path of evolution from the brute to man, 



