104 Synaptomys Cooperii and Synaptomys Stonei. 



It is hard to understand just what Mr Rhoads means. I can 

 find no differences whatever between the lower jaws of S. 

 and cooper ii. 



Let us now look at the geographical distribution of 

 cooperii, and bearing in mind the powerful effect of well defined 

 faunal areas on a species, see what we should expect the 

 Synaptomys of south central New Jersey to be. 



We have Synaptomys cooperii from Minnesota, Iowa, Indiana, 

 Ohio, North Carolina, Maryland and Massachusetts; would it 

 not seem extremely improbable that we should find anything 

 but cooperii in New Jersey? 



Prof. Baird, in his original description of Synaptomys cooperii, 

 says the specimen was "received from Mr. William Cooper of 

 Hoboken. No locality was assigned, but the animal is undoubt 

 edly North American, probably from the New England States 

 or New York; possibly from Iowa or Minnesota." Why not 

 even more probably from New Jersey, as Mr. Cooper lived there ? 



Since writing this article I have taken two more Synaptomys 

 cooperii in Plymouth County, Mass.; one at Plymouth, January 

 15, 1894 [ad. 9 ], and one at Wareham, March 31, 1894 [ad. $ ]. 

 Both were caught in old cranberry bogs, associated with Arvicola 

 r iparius and using their run-ways. 



