PREFACE. 



THE present manual has' for its basis a set of laboratory direc- 

 tions prepared by members of the staff of instructors to meet 

 the needs of the class in general zoology at the Marine Biolog- 

 ical Laboratory of Woods Holl, Massachusetts. Those who 

 were associated with me in the preparation of the first notes 

 were Dr. Robert W. Hall, Dr. James H. McGregor, Mr. Robert 

 A. Budington and Dr. Caswell Grave. Other members of the 

 staff who have either aided me in modifying the original notes 

 or who have added others are Dr. Winterton C. Curtis, Dr. D. 

 H. Tennant, Dr. Otto C. Glaser, Dr. Grant Smith, Dr. John H. 

 McClellan and Dr. Lorande L. Woodruff. Each year for the 

 past six years the directions have been changed where experi- 

 ences indicated changes should be made. 



Probably few instructors will find it desirable for their stu- 

 dents to follow closely all that is given in this manual, but it has 

 seemed better to arrange the matter in a logical order, and in 

 some of the forms to call attention to only the important points 

 of anatomy or adaptation, than to try to make the directions 

 for each form complete in themselves. To make the directions 

 for each form complete would necessarily add much labor for 

 the student and would, by the repetition of well-known facts, 

 tend to blunt some of the new and important points to be gained. 



The type method of laboratory study has for many years been 

 the prevailing method, but care needs to be exercised to keep 

 students from making everything conform to type, and in lead- 

 ing them to see the wonderful adaptations that fit the different 

 animals for their particular lives. The manual is not intended 

 to lead students to a knowledge of comparative anatomy alone, 

 but to an appreciation of adaptation as well. 



It has fallen on me year by year to see that desirable changes 

 were made in the directions, and it has finally been my lot to 

 put them into their present form, but much of the credit be- 

 longs to the men who have been associated with me in the 

 instruction work at the Marine Biological Laboratory. 



THE AUTHOR. 

 May, 1907. 



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