Occasional Papers of the Museum of Zoology 15 



condition of the teeth, and weakness of the skull sutures. For 

 each individual the age is first stated, next the number of embryos 

 if any, and last the length of the embryos in millimeters measured 

 as they lie rolled in the fetal membranes. For embryos too 

 small to measure with field equipment the term small is applied. 

 These records indicate the breeding period of the different 

 species and the number of young. 



Mephitis nigra. Eastern skunk 

 August 19: subadult, o embryos. 



Peromyscus leucopus noveboracensis. 

 Northern white-footed mouse 

 July 16: adult, 3 embryos, size small. 

 July 21: adult, o; adult, o. 

 July 22: adult, 5, 10.5 mm.; subadult, o. 

 July 23: subadult, o. 



July 25: juvenile, o; juvenile, o; juvenile o; subadult, 3, small. 

 July 30: adult, o; adult, o; adult, o; subadult, o. 

 August 2: adult, o; subadult, 2, small; subadult, o; subadult, o. 

 Augusts: adult, s, small; subadult, o. 

 August 23: subadult, o; adult, 5, 10 mm. 



August 24: adult, 5, 8 mm.; adult, o; adult, o; adult, 3, small. 

 August 25: adult, 5, 23 mm.; adult, o; adult, 4, small; adult, 3, small. 

 August 26: subadult, 4, 8 mm.; adult, o. 

 August 29: adult, 4, 17 mm. 



Peromyscus manicidalus bairdii. Prairie 

 white-footed mouse 

 August 7: subadult.o. 

 August 10: adult, 5, 8 mm. 

 August 13: adult, 3, 8 mm.; adult, o. 

 August 20: adult, 5, small. 

 August 28: adult, 4, 17 mm.; adult, 4, 13 mm. 

 August 29: adult, 5, 17 mm. 

 August 30: adult, o; adult, 4, 11 mm. 



Synaptomys cooperi. Cooper lemming-vole 

 August 11: adult, 2, 10 mm. 



Microtiis pennsylvanicus pennsylvaniciis. Pennsylvania vole 

 July 15: adult, 4, not measured; juvenile, o. 

 August 9: subadult, o. 

 August 10: subadult, o; subadult, o. 



