VOL. IV. | Nyctinomus Mohavensis. 363 
As the first two, however, are described from essentially the 
same region, it would seem impossible to treat them as sub- 
species; and as our specimens without exception agree with 
mohavensis in the characters by which it is said to differ from 
Jemorosaccus, it seems best to recognize the two as valid species 
until further comparison is possible. 
The specimens taken February 27 were all procured from 
the shutters of one window on the western side of the building, 
and consisted of males and females in about equal numbers. A 
second visit to the Court-house on March 3 resulted in the cap- 
ture of sixty-seven additional specimens. Of these, thirty-two 
were taken from behind one shutter again on the west side of 
the building, and consisted, as before, of both sexes about 
equally represented. The rest of the second catch, thirty-five in 
number, were taken from behind four different shutters on the 
east side of the Court-house, and proved on examination to con- 
sist of females exclusively. This furnishes additional evidence 
that under certain circumstances the sexes congregate separately. 
Several specimens of this bat have since been taken on the 
University Campus, and at the Hopkins Seaside Laboratory at 
Pacific Grove. We have also had the privilege of examining a 
specimen collected at San Diego, Cal., by Mr. C. H. Marsh. In 
this the lower incisors were 3-3, distinctly bilobate, and in gen- 
eral proportions, and shape of ear, it agreed with our specimens. 
Le Conte has already called attention to the variation in the 
number of lower incisors in Vyctinomus brasiliensis (‘‘Rhinopoma 
carolinense’’), as out of fifteen individuals examined by him 
‘* ore had no incisors on the lower jaw; two had five; three had 
four, and the rest six.’’* ‘The same variation obtains in o- 
havensis. Merriam describes the lower incisors as 2-2, not dis- 
tinctly bifid. But the normal arrangement appears to be 3-3, 
all distinctly bilobate. Thus in forty-five specimens examined 
as to this character, 24 specimens have 6 lower incisors; 9 have 
5, and 12 individuals have 4. The outer incisor when present is 
very small, and so crowded forward as to occupy a precarious 
position in front of the canine, a fact which may account for its 
* Observations on the North American Species of Bats, John Le Conte 
Proc. Acad. Nat. Sci., Phila., 1859, page 43i. 
* 
