The three methods of approach to ecological study are not so distinct as they appear at first thought. With perfecting knowledge the network of interrelations increases and the paths converge. Then also the study of the individual behavior of “social” animals, as ants, white ants, bees, or birds which live and breed in colonies, shows transitional stages from the individual unit to that of the family, the colony, and on to the association. Yet the advantage of each point of view should be recognized as an aid in the analysis and synthesis of any problem. Some students feel that the study of individual ecology should precede that of the associational. Within certain limits this is true, but if our general knowledge of biology had waited for the perfection of our knowledge of the individual cells of animals, the results would have been disastrous to all concerned. Even now our knowledge of these subjects is very incomplete. For similar reasons there should be no delay in studying animal aggregates and associations. A combination of ecological and taxonomic study generally appeals most strongly to those students who have made a specialty of some group of animals. They are familiar with certain forms, have some confidence in taxonomic methods, and frequently have given some attention to habits, life histories, and to collecting. To those who like the descriptive aspect of taxonomy, ecological studies also offer a new field for further description and classification. At present perhaps the majority of ecological students have entered the subject through taxonomy. It is the almost universal verdict of such students that it has required much effort on their part to make the change in the point of view. Such a change cannot be made by a simple resolve, but requires a modification of the habits of the mind, which will be attended by a distinct consciousness of effort. As in other habits, reversion to the older attitude of mind is very easy. This change in point of view is a problem in habit formation, a study of the mental behavior of the ecologist, which is in reality the main topic thus far discussed. One may attempt to make such a change and find that he does not have sufficient modifiability to make it permanent, so that it is only for the moment, during actual collision with some stubborn fact, that he is able to realize ecological relations and an ecological point of view. [Illustration: FIG. 3.--Struggle for Existence on a Clam Flat. Showing the destruction of a colony of Soft Clams by Horse-shoe Crabs (_Limulus_) and Cockles (_Lunatia_), Rowley Reef, Massachusetts. Photo. by Belding, loaned by Mass. Comms. Fisheries and Game. ]