No.416.]] MAMMALS IN SAN MIGUEL ISLAND. 643 
soles naked ; ears sparsely haired, dusky ; tail very sparsely 
haired, coarsely scaly, indistinctly bicolored, blackish, rather 
paler towards base below. 
Young examples are rather darker, less reddish, brown above, 
and the upper surfaces of feet and hands darker brown, less 
yellowish. 
The adults vary but little in color; some specimens are 
yellower above and others more strongly ferruginous. 
MEASUREMENTS. 
| | | ČAR FROM 
Huse, gae | Dem d ae aa room | Wro 
| | HRS gE | 
| d adult | May 5 | .320 |. 140 34 | 18 
8485, topotype | [de m 315 | 140 34 17 
8492,  " Eze soia April 2 6 . 195 32 17 
8495  * |3 H ecu 305 | 42 33 17 
8487,“ | k ah May 2 300 | 10 k 17 
8486, “ Le s April 25 w | DE 1 17 
84906,  * La A ay 6 295 | 120 | 32 17 
B, *" |9.« « 8 |. 290 | neu s 16 
8483, « Le April 30 290 | 435 | 30 18 
8484, « E ON ir ad 390 ^o Bids *» 18 
8489, “ TI May 5 285 | 120 | 30 15 
8488, “ P$." “ 3 285 | 30 [uode 16 
8481, ^ « pe m April 26 285 IIO 39 16 
Bon ^ pa M a ik 280 120 30 17 
8495, o“ Se 5 * 22 275 110 30 17 
Skull, type, old adult 2, basal length, 32.8; occipito-nasal 
length, 35.2; zygomatic width, 18.4; mastoid width, 12.8; 
length of nasals, 15; width of nasals, 4.4; least interorbital 
width, 5.4; width across zygomatic plates, 11.2 ; length of inci- 
sive foramina, 7.4; width of incisive foramina, 3.2 ; length of 
palate, to palatal notch, 16; to end of pterygoid, 22; upper 
tooth row, 5 2; length of single half of mandible, 21 ; lower 
tooth row, 5.2. _ 
_ Remarks. — The San Miguel vesper rat is a strongly marked 
island species, most nearly related to Z. brevicauda, of Trinidad, 
which it precisely resembles in color and character of pelage. 
Its much greater size, bigger foot, and different tail distinguish 
