2 i8 ANIMAL PEDIGREES 



inquiry, which if energetically worked must yield 

 results of great interest and importance. 



In order to understand fossils aright, and to 

 derive from them the full amount of information 

 they are capable of yielding us, it is necessary that 

 we should have a thorough knowledge of the deve- 

 lopment of their living descendants ; and more es- 

 pecially that we should be fully acquainted with 

 the several stages of formation of the shells or 

 other hard parts of the recent forms, which in 

 their fossil representatives are, with rare excep- 

 tions, the only parts sufficiently well preserved to 

 give trustworthy evidence. 



Embryologists have too often confined them- 

 selves to the earlier stages of development, and 

 have unduly neglected the later stages, and more 

 especially the later stages of the skeletal structures. 

 By so doing they have failed to afford to palaeon- 

 tologists the aid which they are peculiarly qualified 

 to give, and which to the palaeontologist would be 

 of the utmost value. Fortunately the mistake is 

 now recognised, and serious efforts are being made 

 to remove the reproach. 



We must now turn to another side of the ques- 

 tion. Although it is undoubtedly true that 

 development is to be regarded as a recapitulation 

 of ancestral phases, and that the embryonic 

 history of an animal presents to us a record of 

 the race history ; yet it is also an undoubted fact, 

 recognised by all writers on embryology, that the 

 record so obtained is neither a complete nor a 

 straightforward one. It is indeed a history, but a 



