THE HOUSE MOUSE 



649 



{E. Museo Lundii, iii., 60; and Danmarks Pattedyr, 90) has drawn 

 attention to the fact that in the relatively small House Mice from 

 Lagoa Santa, Brazil, m\ are in course of reduction, being sometimes 

 wholly lacking, sometimes wanting from one or the other jaw, and 

 when present always smaller than in European examples. In a skull 

 from Cordoba these teeth are absent from both sides of the upper jaw, 

 while they are greatly reduced in the mandible. There is thus ample 

 evidence of the fact that M. musculus is capable of developing new 

 forms adapted for leading a wild life amid foreign surroundings and 

 among strange competitors. 



DIMENSIONS IN MILLIMETRES:— 



Head and 

 body. 



Tail 



^without 



terminal 



hairs). 



Hind foot 

 (without 

 claws). 



Ear 

 (greatest 

 length). 



Weight in 

 grammes. 



SPECIMENS FROM REHiATE, 8UREBT, CAUGHT AND MEASUEED BY L. E. ADAMS. 

 Sexually Iumature of Both Sexes; — 



1. 19th Feb. 1912, average of 7 ; furred 



above, eyes and ears closed . 



2. 19th Feb. 1912, average of 4; furred 



above, eyes and ears closed . 

 8. 19th Feb. 1912, male ; furred above and 



slightly below, eyes and ears closed . 

 4. 19th Feb. 1912, female; fully furred, 



eyes and ears open .... 

 6. 28th Aug. 1913, male ; full first pelage . 



6. 17th Dec. 1912, male .... 



7. 80th Deo. 1912, female .... 



8. 29th April 1913, male ; adult pelage 



above, almost adult below . 



9. 19th Feb. 1912, female; adult pelage 



above, almost adult below . 



10. 29th Aug. 1913, male; complete adult 



pelage 



11. 2nd May 1913, male ; nearly full pelage 



12. 29th Aug. 1913, male ; complete adult 



pelage 



18. 8th Aug. 1913, male ; first pelage below 



14. 9th Aug. 1913, male; complete adult 



pelage 



15. nth Oct. 1911, female; complete adult 



pelage 



IC. Sth Aug. 1913, male; complete adult 

 pelage 



17. Slat Aug. 1918, female ; not quite adult 



pelage below 



18. ISth July 1913, female ; complete adult 



pelage 



19. Jan. 1912, male ; complete adnlt pel- 



age 



20. 16th Feb. 1913, female ; complete adult 



pelage 



21. 29th Aug. 1913, female; adult pelage, 



but imperforate 



22. 1st May 1913, female; adult pelage, but 



imperforate 



3-5 



4 



6 



7 

 8 

 7 

 10 



8-61 



111 



9 



8-6 



9 

 10 



10 



H 

 10 

 13 

 12 

 15 



1 Nos. 8 and 9 are respectively the minimum and maximum of a series of seven recorded in Adams 

 original table. 



VOL. 11. 



