CHAPTER XXXII THE DISTRIBUTION OF ANIMALS TECHNICAL NOTE.--The larger aspects or phenomena of the distribution of animals over the earth on land and in sea cannot be studied personally in the field by the student, but many local features of distribution can be so observed and studied. The restriction of certain kinds of animals to certain kinds of habitat, the presence and character and effectiveness of barriers, some of the modes of distribution, the presence and successful life of introduced foreign species such as the black and brown rats, the English sparrow, the German and Asiatic cockroaches, the gradual change of range or distribution of certain kinds of animals through the influence of a change in environment (caused by man in cutting off forests, cultivating heretofore wild pastures, etc.) all offer favorable and profitable opportunities for personal observation. An excellent and feasible piece of field-work in distribution is the making of a zoological survey of the locality in which the school is situated. A map of the locality should be made on a generous scale, which should include all prominent physical features of the region, such as streams, ponds, hills, woodlands, marshes, etc., and on this map should be indicated the places where the various animals of the local fauna occur. Some of the animal species will have a limited range, and the limits of this range should be shown. This map and faunal list can be added to and perfected by successive classes. For fuller discussions of the geographical distribution of animals see Jordan and Kellogg's "Animal Life," Beddard's "Zoogeography," Heilprin's "The Distribution of Animals," and Wallace's "Geographical Distribution."