LECTURE XVI. 455 



froin the crossing of both elements, or perhaps by natural 

 selection ; no person can decide how this form arose ; but that 

 the intermediate form exists in such a shape that it might have 

 been the result of cross-breeding cannot be doubted. That this 

 race acquired the requisite capacity for existence is rendered 

 evident by its frequent occurrence in a country where at present 

 no monkeys exist, where, therefore, by subsequent changes in 

 the surrounding media the existence of these animals was ren- 

 dered impossible. 



There exist thus intermediate forms of minute transitions and 

 regular transformations. The example of the Grreek monkey 

 shows that the whole structure must be known, and that it is 

 not sufficient to study the skull or the dentition to detect such 

 intermediate forms, and that for this reason our knowledge of 

 fossil forms is too fragmentary for us always to find them out. 



We are certainly told not to make deductions from the un- 

 known. I agree with this perfectly. I do not assert that 

 because an intermediate form has been discovered between 

 Sevinopithecus and Macac^is, there must be one found between 

 the Semnopithecus of the old world and the Gebus of the new ; 

 but I also maintain, that in our fragmentary knowledge we 

 must not, where our knowledge is for the moment at fault, say, 

 thus far and no further ! It is scarcely thirty years since 

 Cuvier said : There exists no fossil monkey, and none can 

 exist : there is no fossil man, and there can be none ; and yet 

 to-day we speak of fossil monkeys as of old acquaintances, 

 and trace back fossil man, not only to the diluvium, but to 

 recent tertiary formations, though some obstinate persons still 

 assert that Cuvier's principle cannot be controverted. It is 

 scarcely twenty years since I learned from Agassiz : Transition 

 beds, palseozoic formations = Empire of Fishes ; there are no 

 reptiles in this period, nor could have existed, as it would 

 have been contrary to the plan of creation. Secondary for- 

 mations (Trias, Jura, Chalk) = Empire of Eep tiles. There are 

 no mammals, nor could be, for the same reason as above. Ter- 

 tiary strata = Empire of Mammals ; there are no human beings 

 nor could have been. Present creation = Empire of Man. 

 Where is at present this exclusive plan of creation ? Reptiles 

 in the Devonian strata, reptiles in coal ; farewell then Empire 



