PREFACE. 



THIS manual has for its basis a set of laboratory directions 

 prepared by the instructors in the Zoology Course given at the 

 Marine Biological Laboratory at Woods Hole, Massachusetts, 

 for the use of students in that course. These manifolded out- 

 lines were first used in 1901. Associated with me in the prep- 

 aration of the first notes were Dr. Robert W. Hall, Dr. James 

 H. McGregor, Mr. Robert A. Budington, and Dr. Caswell Grave. 

 For several years the notes were modified and additions were 

 made before there was any thought of publication. During 

 this period other instructors became members of the staff and 

 added to the directions. These instructors were Dr. Winterton 

 C. Curtis, Dr. D. H. Tennent, Dr. Otto C. Glaser, Dr. Grant 

 Smith, Dr. John H. McClellen, and Dr. Lorande L. Woodruff. 



Since publication, the instructors in this course have offered 

 many suggestions and criticisms that have aided greatly in 

 revisions. I am especially indebted to Dr. Lorande L. Woodruff, 

 who has given much attention to the revision of the Protozoa, 

 and to Dr. Winterton C. Curtis, Dr. Caswell Grave, and Dr. 

 W. C. Allee, who have successively been in charge of this course. 



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. 



Since the first appearance of the manual in book form there 

 have been many suggestions that directions for other forms be 

 included, or that more complete directions be given for some of 

 the forms treated. These suggestions have been followed in 

 many cases. There is, however, danger that students will 



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