162 The Rev. L. Jenyns on the Common Bat of Pennant. 
the description is somewhat more diffuse, there is still the error 
of confounding this species with the Vespertilio murinus of con- 
tinental authors alluded to in the beginning of this paper. 
It would seem, therefore, absolutely necessary to impose a 
new trivial name upon the Common Dat of this country and to 
treat it as nondescript, if there be really no further account of 
it than is to be found in the works of our British naturalists. 
But before taking such a step, it becomes necessary to inquire 
whether it may not be recognized among any other of the spe- 
cies described by foreign authors since the time of Linnzus, 
however distinct from that with which it has been always con- 
founded. It does not seem likely that so common a species in 
this country should be peculiar to it, and not found on the con- 
tinent, where all our other indigenous Vespertilionide are well 
known*; neither is it probable, that if it is to be met with in 
equal plenty abroad, it should have wholly escaped notice. Now - 
on this point I am inclined to answer in the affirmative; and, 
though I give my opinion with much diffidence, I would ask, in 
what essential points our Common Dat differs from the Pipistrelle 
of Daubenton and succeeding writers. After a careful examina- 
tion of very many specimens, and an accurate comparison of 
these with the descriptions annexed by Daubenton and Geof- 
froy to that species, I can see no material distinction between 
them. It is true that Daubenton’s dimensions of the Pipistrelle, 
as well as those given by Desmarest in his Mammalogie, 
somewhat less than in the generality of our English specimens : 
but such appear to have been taken from immature individuals ; 
since the proportions between the several parts are still kept 
up, and the actual measurements agree in most particulars with. | 
those of. one or two. small specimens in my possession. Geoffroy, 
* The Fe empero pygmaus, discovered by Dr. Leachi in € appears as yet 
to be an exception. 
however, 
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