104 



REVISION OF AMERICAN MOLES— TRUE. 



It will be seen that the average total length of the females is a little 

 greater than tliat of the males, which is probably due to the presence 

 of more well developed individuals among the former than the latter 

 in the series, and not to any real differen.ce in size between the sexes, 

 seeing that the average length of tail and hind foot is practically iden- 

 tical in both sexes. At all events the averages for the combined series 

 of .■).'> s])ecimens are as follows: Total length, 113.0 mm.; tail, 37.1 mm.; 

 hind foot, 1G.(> mm. The maximums are as follows: Total length, 

 11*3 mm.; tail, 41.5 mm.; hind foot, 17.") nun. I have measurements of 

 only one fresh specimen from farther south to comi)are with these. It 

 is from :\Iarin County, California (No. 258."), A. M.): Total length, 

 1 17.5 mm.; tail, 38.1 mm. It will be seen that this exceeds the average 

 of the Sumas scries, but falls short of the maximum. So far as it goes, 

 therefore, it does not indicate any increase in size southward. 



The skull of this California specimen exceeds that of the Sumas 

 S[)ecimen, which has the maximum external i)roportions by eight-tenths 

 of a millimeter, and is the largest skull examined. There is only one 

 other complete adult California skull (No. 1*4010, D. A., Crescent City, 

 California), and this equals the largest of the Sujnas series, and exceeds 

 the average of the same by four-tenths of a millimeter. 



Measurements of six dry skins from Washington and three from 

 Califoi-nia, all by the same collector, give the following results: 



These dimensions are probably nearly correct, and would appear to 

 indicate a more considerable increase southward than is shown by the 

 other data, but as in the case of all dry skins, results from measure- 

 ments are lik(>ly to prove unreliable. 



It is probably safe to assume that there is a slight increas(» in size 

 toward the South in this species. 



DATIOS or MOLT. 



The s])ecimens {)f Xeiirotrichtis examined*give some indication of the 

 pei iods of changing the fur, but are not suflicient to determine tlu', 

 dates with exactitude. A male from Steihuioom, Washington, taken 

 Octoberl2,has new fur concealed on the ])osterior half of the backandold 

 fur elsewhere. Another individual from the same jtlace (and su])i)ose(l to 

 be a female), taken October 9, has the change much furthei- advanced, 

 tlie new fur covering all the back. The under surfaces still retain the 

 old fur. All that can be learned from these two specimens is that the 

 fall molt takes place in October. Why the female is so much further 

 advance<l than the male is not exi)lainable. 



