PREFACE. ix 



a regular market commodity, partly because it is, to my 

 mind, quite unrivalled for the study of the vertebrate nervous 

 system. The Rabbit is chosen in preference to the Dog or 

 Cat either of which, and especially the former, would have 

 been preferable for some reasons because it can be more 

 readily obtained in quantity; its size, moreover, makes it 

 more suitable than the Rat. The Green Lizard and the 

 Lamprey cannot always be depended on, but, as they can 

 both be easily preserved whole in alcohol, this is of . less 

 consequence than in the other cases. It was not thought 

 necessary to include an amphibian, since the Frog is fully 

 described in the Elementary Biology. 



The labour of correcting the proofs and of superintending 

 the drawing on wood and engraving of the illustrations has 

 fallen upon my brother, Mr. W. N. Parker, F.Z.S., without 

 whose help the publication would have been almost out of 

 the question. Besides the editorial work, he has made out 

 several points in the anatomy of the Cod and Lizard, 

 which, owing to lack of material, I was unable to decide 

 myself. Many important omissions and some actual errors 

 have thus been avoided. 



I am indebted to Professor Huxley for having kindly read 

 over such parts of the work as were written when I left 

 England, and for valuable suggestions thereon. But beyond 

 this, I shall always feel that any value the book may possess 

 is very largely due to the example set me by Professor Huxley 

 during all the years I had the good fortune to be associated 

 with him. 



