136 WALTER LOUIS HAHN. 



and rest; feeding habits; breeding habits; and locomotion, includ- 

 ing the sense of direction and means of avoiding obstacles. The 

 senses of direction and means of avoiding obstacles have been 

 investigated experimentally. Studies on the other topics have 

 been carried on largely by observation on free and captive 

 animals. 



The work was prosecuted from September 20, 1906, to Sep- 

 tember 7, 1907, while the author held the Speleological Fellow- 

 ship in Indiana University with residence at the University's Cave 

 Farm three miles east of Mitchell, Indiana. Later the work was 

 continued in the laboratory of the University at Bloomington, 

 Indiana. There are sev^eral caves in the vicinity of both places 

 which are inhabited by a large number of bats, thus affording 

 exceptional opportunities for the study. 



Some of the notes, especially those on breeding habits, are 

 very brief. However, it is thought best to include them, together 

 with such facts as those contained in the section on morphological 

 peculiarities, in order to give a more complete idea of the biology 

 of the animals. The experimental studies also need to be con- 

 tinued. 



The data presented are in part psychological, but it is the pur- 

 pose of the present paper to treat it from a biological rather than 

 a psychological standpoint. 



The work has been carried on under the direction of Dr. C. 

 H. Eigenmann, professor of zoology in Indiana University, to 

 whom I am indebted for constant advice and criticism. My 

 thanks are also due to Dr. Charles Zeleny, associate professor of 

 zoology, for helpful suggestions and for aid in revising the 

 manuscript. 



Previous Work. 



Published observations on the habits of North American Bats 

 are limited to scattered paragraphs in natural histories and taxo- 

 nomic papers. A number of short papers have been published 

 on English, and a few on Continental European bats. The only 

 extensive studies on the subject are two by Rollinat and Troues- 

 sart, the first on the reproduction of the Murine {Vespertllio 

 inuri)ius) in 1896, and the second on the sense of direction, in 

 1900. 



