KDNOI-. SV. VET. AKADEMIENS HANDUNGAR. BAND 57- NIO 2. I > 



Rattus rattus griseiventer. Bonh. 



Fascicali Malayensis. Part I. 1903 p. 30. 



2 Doi Par Sakeng. Northwestern Siarn, i7 /t 1914. — Nose to vent == 160 mm.: tail = 204 mm.; 

 hindfoot = 33 mm. 



A house Rat though apparently not as comnion as the other members of tlie rattus- 

 group found in Siarn. The tail is brown instead of black as in some specimens of true 

 Rattus rattus griseiventer from the Malay Peninsula, which I have used for comparison. 



The general colouration is also somewhat paler. 



Skull measurements: 



Greatest length — 40,o; zygoniatie width = 18,8; width of brain case = 15,t>; 

 length of palate from henselion = 18,s; breadth of palate between m l = 2,5; diastema 

 = 9,8; length of foramina incisiva — 6,5; length of nasals mesially = 14,o; breadth of 

 nasals anteriorly = 3,s; breadth of nasals posteriorly — 1,2; least interorbital breadth 

 = 6,0; maxillary toothrow — 7,i mm. 



Rattus concolor. Blyth. 



j Koli Lak, Sianiese Malaya, !f /u 1914. — Nose to verit *= 130 mm.: tail = 113 mm.; hindfoot — 

 2ö mm. — J 1 Koh Lak M /n 1914.' — Nose to vent = 112 mm ; hindfoot 24 mm. — 2 Koh Lak »"/11 1914. 

 Nose to vent = 105 mm.; tail = 143 mm.; hindfoot = 24 mm. — 2 Koh Lak ' 12 1914. — Nose to 

 vent — 110 mm.; tail — 140 mm.; hindfoot — 24 mm. — J 1 Koh Lak 1 /i2 1914. — Nose to vent = 120 mm : 

 tail =118 mm.: hindfoot 25 mm. — 2 Koh Lak V'- 1914. — Nose to vent =115 mm.: tail = 140 min.: 

 hindfoot = 25 min. 



All these specimens are absolutely similar to true Rattus concolor Blyth from differ- 

 ent parts of the Malay Peninsula with which I have compared them. 

 Very plentiful in the houses at Koh Lak. 



Skull measurements S 



Greatest lengtli 28,5 mm 



Coudylus to gtiathion '-Jti. i 



Basicranial length 



Zygomatic breadth 12,8 



Width of brain case 11,9 



Least interorbital breadth 4,2 



Length of nasals mosially .... 9,5 



Breadth of nasals anteriorly ... 2,7 



Breadth of nasals posteriorly .... 1,5 



Diastemu 6,5 



Palatal length from henselion ... 12,2 



Length of foramina incisiva .... 5,3 



Maxillarv toothrow . . .... 4,4 



29,8 inni. 



30,3 mm. 



— 



27,4 



27,9 



— 





20,7 



— 



13,o 





12,5 



12,c 



12,5 



12,2 



4,3 



4,3 



4,4 



10,3 



10,2 



10,5 



3,0 



3,o 



2,7 



1,5 



1,5 



1,3 



7,5 



7,8 



7,0 



13.1 



14,0 



12,6 



5,3 



5,1 



4.8 



4,7 • 



4,5 



4.5 



