INTRODUCTION 



THESE directions for dissection are intended eventually to 

 include representatives of all the major groups of vertebrates. 

 Each is complete in itself and is issued separately so that 

 laboratories may select those forms best adapted for their courses. 

 The directions have been tested by several years' use and are 

 thought to have a distinct pedagogic value in that they do not 

 so much tell the student what he will find, but instead ask him 

 what he does find. He thus obtains his information from the 

 specimen, not from the printed page. For similar reasons illus- 

 trations have been omitted; students sometimes find it easier 

 to copy the published figure than to work out the points for 

 themselves. 



No attempt has been made to follow out every system of 

 organs completely, but each has been traced far enough to give 

 a good knowledge of the more important structures to use as a 

 basis for comparisons. The student by following the directions 

 may obtain a knowledge of the general anatomy of the animal 

 studied, but this knowledge of itself has little value. More 

 important is the benefit to be gained by comparing the different 

 forms dissected, tracing as far as possible their resemblances and 

 differences. Hence in his dissection the student should con- 

 tinually recall the conditions existing in all other animals as he 

 is tracing out each part. 



More than this: he should read the general statements given 

 in manuals of vertebrate structure as he takes up each organ 

 or system of organs, thus correlating his discoveries and making 

 them a part of one general whole. It would be well to go farther 

 and read the accounts of the development of the organs in 

 question in some of the text-books of vertebrate embryology. It 

 is only in this way that an explanation of many peculiarities of 

 structure may be obtained. 



Unless explicitly used otherwise the terms right and left in 

 the following directions apply to the right and left of the animal 

 being dissected, not of the student. Anterior and posterior 



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