644 THE AMERICAN NATURALIST. 
it, externally, from the Trinidad species, and the skulls of the 
two can easily be distinguished. 
Z. seorsus was an abundant animal in San Miguel Island, 
inhabiting the dense, swampy woods, and Mr. Brown found no 
difficulty in trapping it in numbers. 
That the vesper rat of San Miguel Island should be so like 
the Trinidad species is interesting, especially so as the yellow 
honey creeper of the island (Cwreba cerinoclunis Bangs) is 
much more nearly related to C. /uteola of Venezuela, Trinidad, 
and northeastern Colombia than to C. mexicana of the neigh- 
boring coasts of Panama and Colombia. 
Mus musculus Linn. 
One adult ¢, taken April 20, 1900. 
Mus rattus rattus Linn. 
One adult 2, taken April 20, 1900. 
Mus rattus alexandrinus (Geoff.). 
One adult 2, taken April 23, 1900. 
The three introduced species of Mus could not have been 
very numerous in San Miguel, as one individual of each was 
all that fell into Mr. Brown's traps in over three weeks of 
collecting. 
Vampyrops helleri Peters. 
One adult 9, taken April 25, 1900. 
Mr. Gerrit S. Miller, Jr., tells me that this is the only exam- 
ple of this rare bat that he has seen, but the specimen agrees 
so perfectly with the description that he has little doubt of its 
being true V. kelleri. 
Hemiderma brevicaudum (Wied.). 
One adult 4, taken April 25. 
