268 



PRINCIPLES OF ANIMAL BIOLOGY 



Relations of Taxonomy. — Classification has wide connections with 

 nearly all other phases of l)iolofj;y. In a practical manner every biologist 

 has occasional or frequent use for the technical knowledge of the syste- 

 matist, and this requirement is not a purely formal one. Many investi- 

 gations whose principal aim is entirely apart from classification must 

 nevertheless constantly use the data of taxonomy. Thus the zoogcog- 

 rapher, as will be apparent in Chapter XIV, is not primarily interested 

 in classification; but in order to discover the principles which have 

 guided migration or determined extinction in the past he must be thor- 

 oughly conversant with the taxonomy of the group whose distribution he 

 studies. The paleontologist also requires a knowledge of classification, 

 not only of extinct forms but of their living relatives. The work of the 

 physiologist frequently involves the question of relationship, as does that 

 also of the ecologist. Indeed, every biological field is in very close con- 

 nection with taxonomy. 



This intimate relation is not one-sided, for each of the phases of 

 biology contributes to a knowledge of classification. Distribution and 

 fossil forms supply information where morphology fails, or may refute 

 conclusions based on morphology alone. Physiological facts must be 

 taken into account in explaining the formation of species. Ecological 

 relations must be understood if certain taxonomic questions are to be 

 correctly answered. In practice this close relation between taxonomy 

 and the other phases of biology is not always observed, but all of them 

 suffer from its neglect. 



TABULAR VIEW OF THE CLASSIFICATION OF ANIMALS AS FAR AS ORDERS 



The complete classification of animals includes, of course, extinct 

 and living forms, and there are differences of opinion as to the position 

 and composition of many groups. The following classification, including 

 the living and a few fossil forms, now in use in the Zoological Laboratory 

 of the University of Michigan, has been compiled from many sources. 



PHYLUM I. PROTOZOA 



Class I. Rhizopoda 

 Order 1. Lobosa 

 Order 2. Heliozoa 

 Order 3. Radiolaria 

 Order 4. Foraminifera 



Class II. Mastigophora 

 Order 1. Flagellata 

 Order 2. Choanoflagellata 

 Order 3. Dinoflagellata 

 Order 4. Cystoflagellata 



Class ni. Sporozoa 



SuBt'LA.s.s I. Telosporidia 

 Order 1. Gregarinida 



Order 2. Coccidiidea 

 Order 3. Haimosporidia 



Subclass II. Neosporidia 

 Order 1. Myxosporidia 

 Order 2. Sarcosporidia 

 Class IV, Infusoria 



Subclass I. Ciliata 

 Order 1. Holotricha 

 Order 2. Heterotriclia 

 Order 3. Hypotriclia 

 Order 4. Peritricha 



Subclass II. Suctouia 



