412 MR. OLDFIELD THOMAS ON MAMMALS [^Pl"- 23, 



Detailed measurements : — 



Head and hodv. Tail, 

 mm. 



J . 881 (Type). 104 



J. 890 104 



?. 882 103 



$. 891 102 



Skull of type — greatest length 28 mm. ; basilar length 21-8 ; 

 zygomatic breadth 13"7 ; interoi'bital breadth 4"6 ; palate length 

 13*1 ; diastema 9 ; palatal foramina 5"7 ; length of upper molar 

 series 3-7. 



Type. Adult male. B.M. No. 7.2.5.42. Original number 881. 

 Collected at Darine, 11th August, 1906. 



This is no doubt the " Mus sylvaticus " of Nikolsky's work, and 

 indeed it is probable that all the Long-tailed Field Mice that 

 have been recorded from the Far East of Asia belong to this or 

 some closely allied form, with 2 — 2 = 8 mammae, and that none 

 of them are leally members of the M. sylvaticus group, with 

 1 — 2 = 6 mamma?. 



The following is a short synopsis of the Japanese and Korean 

 forms of Jlicromys, which have been referred to or described in 

 the present series of papers : — 



A. Size large. Hind foot (s. u.) over 21 mm. and skull 



over 25. Supraorbital edges ridged. 



a. Back not lineated 31. speciosits. 



fl2. Tail shorter than Iwad and bod}'. 



fl-*. Foot large, 26-28 mm. in adults. Hokkaido ... M. s. ainit. 

 l'^. Foot medium, 22-24 mm. in adults. 



n^. Tail generally over 100 mm. Hondo &c' M. s. sfeciostis. 



i-*. Tail 90 mm. or less. Oki Is M. s. navigator. 



b^. Tail longer than head and bodj^. 



c^. Ears longer, 15-16 mm. Korea JHf. s. peninsiilce. 



d^. Ears shorter, 14-15 mm. Saghalien M. s. gUiaciis. 



h. Back with a more or less distinct median line. 



Korea M. agra rius. 



B. Size smaller. Hind toot u^nder 21 mm. and skull 



under 25. Supraorbital edges rounded M. geisha. 



c. Ears smaller, averaging about 13 mm. Saghalien M. g. hokkaidi. 



d. Ears larger, generallj- about 14 mm. 



c". Size larger, tail longer. Head and bodj' 85-95 mm. 

 Tail 90-100 mm. 



e^. Hind foot shorter, 18-20 mm. Hondo &c ^•5'- geisha. 



f^. Hind foot longer, 20-21 mm. Yakushima 31. g. yakui. 



d-. Size smaller, tail shorter. Head and body about 



80 mm. Tail 80 mm. Oki Is ! 31. g. celatus. 



16. MiCROMYS SPECIOSUS AINU Thos. 



18 from Ochiai, Central Hokkaido, and Kuchan, 30 miles 

 S.W. of Sapporo. 



17. MiCROMYS GEISHA HOKKAIDI TllOS. 



51 from Ochiai and Kuchan, Hokkaido. 



