Vlll PREFACE. 



either case, the necessary thing is an acquaintance with the 

 complex structure and the life-history of both the higher 

 animals we meet upon the farm, which may serve as host, 

 and also of the smaller organisms met along with them, whether 

 injurious or beneficial, parasitic or leading an independent ex- 

 istence. With an injurious insect, for example, there is some 

 period when it is open to attack : our observation should 

 enable us to discover this period, and our science to suggest an 

 appropriate weapon. In the same way our domestic animals 

 are weak at certain points and at certain times : only an 

 intimate knowledge of their organisation and their habits will 

 enable us to apply the corresponding safeguards. 



In the following text-book the writer has endeavoured to 

 summarise the habits, characters, and development of the 

 animals that may be met with in farm and garden. Groups 

 possessing little or no economic importance have been but 

 briefly referred to, such as the Ccelenterates, Sponges, and 

 Eohinoderms. On the other hand, the structure of one do- 

 mestic animal, the horse, has been treated at some length. 



It is hoped that the book may be of service to the farmer ; 

 but it is primarily written for the rapidly increasing class of 

 students in our Agricultural Colleges, &c. In their hands 

 lies the future of scientific agriculture, in the development of 

 which economic zoology must play not perhaps the least part. 



My thanks must here be expressed to Sir George Brown, 

 K.C.B., for kindly revising the chapter on the Anatomy of 

 the Horse, and for other help generally ; to Dr Hans Gadow 

 for the great trouble he has taken in examining the proof- 

 sheets of chapters xiv. and xv., and for his valuable advice in 

 other matters. The chapters on Mites and Insects have been 

 read over by Mr (now Sir) Charles Whitehead ; and to him 

 1 tender my grateful thanks, not only for his help in examin- 

 ing the proofs, but also for allowing me the use of some of 

 his excellent figures from the publications of the Board of 

 Agriculture. In connection with the latter, I must here 



