Biological Station 13. 



tiles occurring in the region are collected, identified and studied in 

 both field and laboratory. Particular attention is given to the ecology 

 of the several species and correlated studies of the food, habitats, 

 enemies and interrelations of the various species are made. The 

 general problems of evolution, distribution and taxonomy are con- 

 sidered as opportunity offers. Although most of the work is given in 

 the field, attention to precise methods of observation and to the cor- 

 rect use of data is required. 



Thursday. Two hours credit. Assistant Professor Ellis. 



Prerequisite : Elementary collegiate zoology. 



This course gives one hour credit to graduate students. Such 

 students, wishing full credit, must perform extra work, and will reg- 

 ister for Course 101a. 



103. The Natural History of Invertebrate Animals with Refer- 

 ence to the Principles of Ecology. — The course will consist of a care- 

 ful examination of the typical aquatic habitats of the region. This- 

 will involve the collection and identification of forms, the determina- 

 tion of their life histories and structural adaptations and an analysis 

 of the environmental factors, biological and physical, influencing 

 them. In each habitat only those forms will be considered which are 

 of importance in presenting the facts and principles of ecology. 

 Especial attention will be given to analysis of those factors in the 

 lake which make it a suitable abode for organisms. Each student 

 will have actual experience in determining depths, temperature, trans- 

 parency to light, food content of the water and such other matters 

 as fall within the scope of this analysis. The field work will be 

 supplemented by lectures and conferences, so that at the end of the 

 season the student will have a fairly comprehensive picture of the 

 conditions of aquatic life and how animals are affected by these con- 

 ditions. 



The course is planned particularly for prospective teachers of 

 biology. 



Wednesday and Friday. Four hours credit. Assistant Professor 

 Welch. 



Prerequisite : Elementary collegiate zoology. 



This course gives two hours credit to graduates, who may ob- 

 tain full credit by registration in Course 103^. 



105. The Natural History of Insects. — This course is intended 

 to give the student a general acquaintance with the insects of the 

 region and to afford opportunity for the study of the various forms 

 in their native habitats. Field studies are made of the life histories, 

 habits, and activities of insects belonging to various orders. Em- 

 phasis is placed upon the relation of insects to their environment, and 

 upon economic relations. Some work on the morphology and physiol- 

 ogy of insects is included. Instruction is given in the approved meth- 



