The Cotton Mouse, Peromyscus Gossypinus. 125 



band of nearly black ; a black orbital ring ; under parts grayish white ; 

 the hairs plumbeous at base; ears black; tail bicolored, black above, 

 grayish white below ; feet and hands grayish white. 



Size. Average measurements of three adult specimens from the type 

 locality: total length, 168.33; tail vertebra?, 76.66; hind foot, 23.66. 

 Average measurements of twenty adult specimens from Gibson, Terre 

 Bonne Parish, Louisiana: total length, 169.85; tail vertebrae, 77.85 ; hind 

 foot, 22. Maximum size (of largest old adult in above average) : total 

 length, 184 ; tail vertebra, 86 ; hind foot, 22. 



Remarks. The young of Peromyscus gossypinus nigriculus are very dark 

 colored, both in the nursing and the second pelage, and can usually be 

 separated, both by their dark color and their smaller size, from the young 

 of corresponding age of gossypinus or of palmarius. 



This form appears to be confined to the heavy swamps of the bayou 

 region, and probably does not occur farther from the coast than the limits 

 of these swamps. Although Mr. Small trapped persistently in several 

 localities in the prairie and pine regions of central Louisiana, he failed to 

 get a single specimen of any Peromyscus in such places and concluded 

 that none occur north of the bayous. 



Specimens examined, 89, from the following localities in Louisiana : Bur- 

 bridge, Plaquemines Parish, 5 ; Gibson, Terre Bonne Parish, 56; Pow- 

 hatan Plantation (near Gibson), 28. 



