AMPHIBIANS 'AND REPTILES. 259 



(Ruthven 1909). We found the species not uncommon in the sand 

 region. 



Thamnophis butleri. Thi.-5 garter-snake inhabits Indiana, Ohio, 

 western Pennsylvania and southern Michigan. The most northern 

 record for the species, as well as for the state, has hitherto been Oak- 

 land County, Michigan. Three specimens were found in Huron 

 County,— two on Stony Island and one at Rush Lake (neither locality in 

 the sand region), — which extends the range considerably to the 

 northward. 



It will be seen that of the forms in this group Eumeces quinqnelineatus 

 and Thamnophis butleri probably also occur in the interior of the state, 

 so that the milder climate of this coast cannot be said to be of influence 

 in introducing them farther northward than in the interior. On the 

 other hand, if Elophe vulpinus and Heterodon platyrhimis also occur in 

 the interior it is not a little singular that they have not been found at 

 Ann Arbor, Lansing, or Olivet. At first sight it appears that this 

 distribution may be accounted for on the basis of temperature, for 

 both species may be called abundant in the sand region, and, further- 

 more, Eumeces quinquelineatus is certainly much more common there 

 than in the interior. In this connection it is interesting to note that 

 these forms are apparently not only confined to this general region 

 but also to the very limited confines of the sand region, which the more 

 equable temperature of this coast would not rec[uire, that Heterodon 

 platyrhinus prefers sandy regions and has been found elsewhere in 

 lower Michigan only in such areas (Ruthven, 1909), and that Elaphe 

 vulpinus and Eumeces quinquelineatus were by far the most abundant 

 in this region in the dryest and sandiest habitats. In view of these 

 things I believe the explanation for the fact that these forms are here 

 introduced beyond the major part of their range, or at least occur here 

 more abundantly than in the interior, is to be found not so much in the 

 more equable temperature as in the higher summer temperature, sandy 

 soil and general aridity of the upland habitats of the sand region. 



HABITAT RELATIONS OF THE FAUNA. 



As regards their habitat relations the amphil)ians and reptiles of the 

 region studied fall into several groups, the forms of which are particu- 

 larly adapted to the conditions of life in the habitats in which they are 

 found. 



A. Aquatic habitats. Xone of the reptiles and amphibians obtained 

 are deep water, aquatic-breathing forms, although the fishermen 

 informed us that Necturus moculosus is frequently found in their 

 pound-nets off Sand Point. Most of the forms that are associated 



