16 HERPETOLOGY OF MICHIGAN. 



16. Ruthven, Alexander G. The Cold-Blooded Vertebrates of 

 Isle Rovale. Report Geological Survey of Michigan, 1909. A sum- 

 mary of the amphibian fauna of Isle Royale, based largely npon the 

 results of the Universitj' of Michigan Museum expeditions to the 

 island in 1901 and 1905. 



17. Ruthyen, Alexander G. Notes on Michigan Reptiles and 

 Amphibians. Eleventh Ann. Report Michigan Academy of Science, 

 31)09. This paper places on record some miscellaneous data upon 

 the amphibians of Michigan. The writer refers the Michigan wood 

 frogs to Rana cantci'brigensis rather than Rcma sylvatica. 



^18. Smith, Bertram G. The Nests and Larvae of Necturus. Bio- 

 logical Bulletin, Vol. XX, 1911. A larval specimen taken from the 

 Detroit River, Xov. 21, 1906, is described. 



METHODS OF STUDY. 



The amphibians are a group of animals that Avill furnish many 

 interesting problems to Michigan students. In the first place, while 

 most observers of nature know something of their habits and con- 

 siderable has been published on the subject, there is still much 

 to be done upon the species to be found within our limits. Added 

 to this is the fact that the species are not difficult to observe in the 

 field after one becomes familiar w4th their haunts. 



In taking up the systematic study of amphibians, it is desirable 

 first to become familiar with the general characters of the group. 

 The best method of doing this is to dissect a specimen, following the 

 directions in some manual on the subject. The anatomy is treated 

 in most vertebrate zoologies. The Frog Book, by Mary O. Dicker- 

 son, gives an excellent account of the characters used in the classi- 

 fication of the tailless forms, but unfortunately there is nothing at 

 present available on the tailed amphibians. Other books which 

 will prove helpful are, The Batrachians and Reptiles of the State 

 of Indiana, by O. P. Hay, A Manual of the Vertebrate Animals of 

 the Northern United States, by David Starr Jordan, and The 

 Batrachia of North America, by E. D. Cope, although the latter is 

 at present difficult to obtain and is for the most part technical and 

 rather difficult for the beginner. 



The external characters are sufficient for the identification of the 

 Michigan species and are alone used in this work. The points to be 

 considered in the identification are : — first, presence or absence 

 of a tail in the adult state. This at once separates the two orders 

 found in this region, the Salientia (tailless forms) and Caudata 



1 Since this bibliography was compiled two papers have been published, Thompson, 1911, 

 and Ruthven, 1911a, containing records from Cass and Huron counties. 



