INTRODUCTION. 



IN many of our natural history museums one room is 

 devoted to a Synoptic Collection of animals. The stu- 

 dent who wishes to get a comprehensive view of the 

 whole animal kingdom spends most of his time on such 

 a collection, since it embraces representative forms of 

 all the principal groups from the simplest protozoan to 

 the most complex mammal; in other words, from the Pro- 

 tamoeba to man inclusive. 



It may be truly said that mankind is seeking as never 

 before for a rational explanation of the origin and the 

 development of animal life upon our earth. The more 

 strenuous this search, the more imperative is the demand 

 made upon naturalists to present in their museums, so far 

 as possible, the most advanced knowledge concerning 

 these problems. 



At the present time, therefore, it is not enough that 

 a Synoptic Collection consist merely of specimens of 

 animals effectively or artistically arranged. Neither is it 

 sufficient that such a collection consist of species placed 

 together by some arbitrary and artificial method. 



The student of the New Zoology demands that rela- 

 tionship shall be the basis of classification, and that not 

 only the descendants living to day shall be represented, 

 but also their primitive ancestors that existed in an early 

 geologic age. Indeed, a genealogical classification of 

 animals is the goal to be striven for constantly by the 

 naturalist of the twentieth century. The recognition of 

 the possibility of such a classification tends toward the 

 unification of collections which have hitherto remained 

 isolated. For instance, it has been customary to place 



