68 BXJLUSTIN 99, UNITED STATES NATIONAL MUSEUM. 



RATTUS RATTUS KIJABIUS (Allen). 



1903. Mus hijabius Allen, Bull. Amer. Mus. Nat. Hist., vol. 36, p. 109. March 

 19. (Kijabe, British East Africa; type in Amer. Mus., New York.) 



1911. Mus (Epimys?) muansx Matschie, Sitz.-ber. Ges. nat. Freunde Berlin, 

 1911, p. 340. October. (Muansa, German East Africa; type in Ber- 

 lin Mus.) 



1916. Epimys jujensis Lonnberg, Arkiv for Zool., vol. 10, No. 12, p. 10. May. 

 (Juja Farm, British East Africa; type in R. Nat. Hist. Mus., Stockholm.) 



Specimens. — Fifty-nine, from the following localities: 



British East Africa: Changamwc, 17, including 3 in alcohol 

 (Mearns) ; Juja Farm, 7 (Loring, Mearns) ; Kapiti Plains, 11 (Loring) ; 

 Mazeras, 13 (Heller) ; Mount Mbololo, 1 (Heller) ; Nairobi, 8, including 

 2 in alcohol (Mearns) ; Ulukenia Hills, 2 (Loring) . 



This rat has frequently been recorded from East Africa under the 

 name Epimys (or Mas) rattus. Its origin is uncertain, but from 

 the fact that it is found only along the railroad or about the older 

 settlements and highways of trade, it may safely be assumed that 

 the animal was introduced by man. No specimen in the museum 

 series is typical of true rattus of northern Europe or of the sub- 

 species alexandrinus of the Mediterranean shores of Europe and 

 northern Africa. All are to a certain extent intermediate in color 

 between these two forms and resemble very closely the known 

 hybrids or crosses of rattus and alexandrinus frequently found in the 

 southern United States. The series as a whole is very uniform in 

 color and there is httle variation in the shade of the underparts or 

 feet. The color is about that described by Bonhote ^ for his "typical 

 alexandrinus," which is clearly not the alexandrinus of Geoffroy. 



This East African form of rattus, whatever its origin, has appar- 

 ently had four distinctive names based upon it, Mjahius Allen, 1909; 

 muansse Matschie, 1911; rattiformis Matschie, 1915;^ and jujensis 

 Lonnberg, 1916. Inasmuch as the form is certainly not typical of 

 either rattus or alexandrinus, it seems best, until a more satisfactory 

 solution of the case is worked out, to use for it the first name actually 

 given to it in East Africa. Doctor Allen has kindly sent me for 

 examination the type and three topotypes of his Mus Mjahius for 

 study in this connection and as they prove to represent the form 

 under discussion the name Rattus rattus Jcijalius may be applied to 

 it. The type is a young adult, but has the teeth worn more than 

 usual at its age and considerably more than the teeth of the some- 

 what larger skuU of another specimen in the type series. 



Measurements of the type skull of Tcijabius (Amer. Mus. Nat. Hist., 

 27881, male) and of a topotype female, older, but with the teeth less 



J Proc. Zool. Soc. London, 1910, p. 655. October. 



>" Mas {Epimys) rattiforviis Matschie, Sitz.-ber. Ges. Nat. Freunde, Berlin, 1915, pp. 98-99." Type 

 locality, Amani, Usambara, German East Africa. I have not seen the description but judge that the 

 animal is the East African "rattus." 



