PEEFACE. 



IN the preparation of the following pages the author has 

 had two objects in view : that of presenting to his readers 

 such of the more significant facts connected with the past and 

 present distribution of animal life as might lead to a proper 

 conception of the relations of existing faunas ; and, secondly, 

 that of furnishing to the student a work of general refer- 

 ence, wherein the more salient features of the geography and 

 geology of animal forms could be sought after and readily 

 found. The need of such a work has been frequently felt 

 and expressed. As far as he is aware, no work of that kind 

 has as yet appeared, and therefore, to a certain extent, this 

 publication stands alone in the field it is intended to cover. 

 Necessarily, much that it embraces can be found elsewhere, 

 and treated even at considerably greater length ; but the mat- 

 ter is not contained under a single cover, and where a special 

 subject is expounded in extenso the treatment is usually too 

 exhaustive to permit of immediate use by the general reader. 

 This applies particularly to zoogeography. With reference 

 to geological distribution there is little connectedly written 

 indeed, beyond what is found in text-books largely devoted 

 to cognate subjects, practically nothing. Moreover, what little 

 of connected literature on the subject we do possess is almost 



