

? 



A COURSE 



OF 



PRACTICAL INSTRUCTION 



IN 



ELEMENTARY BIOLOGY 



V. 



BY \V- 



^./<->> 



' 



T. H. HUXLEY, LL.D., Si-c. R.S., 



\^^^ 



\SSISTED I'.V 



H. N. MARTIN, B.A., M.B., D.Sc., 



I'ROFKSSOR OF BIOLOGY IN JOHNS HOPKINS UNIVERSITY, I'.ALTlMoRK 



I-F.LIO\Y OF CHRIST'S COLLEGE, CAMBRIDGE, AND OF 



KNIVERSITY COLLEGE, LONDON. 



SECOND EDITION, REVISED. 



Donbon nub ICcu) york : 

 MACMILLAN AND CO 



1876. 



