334 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of Milwaukee, Prof. Z. P. Metcalf of the North Carolina College of 
Agriculture, Prof. F. Payne of Indiana University, and Mr. M. L. 
Church of Marshall, N. C. 
GENERIC AFFINITIES. 
The Big-eared Bats of the genus Corynorhinus take the place of the 
Old World vespertilionine genus Plecotus in North America. In 
essential characters the two genera are very similar, and are evidently 
closely related. Miller (1907, p. 225) in his “ Families and Genera of 
Bats” considers that “the great development of the glandular masses 
on muzzle, and the absence of the distinct lachrymal ridge, distinguish 
this genus sufficiently from Plecotus,”’ to which LeConte and con- 
temporary writers at first referred specimens. The shape of the 
nostrils is also diagnostic, but the presence of a distinct lachrymal 
ridge in a new species from Mexico (see p. 352), invalidates that charac- 
ter as distinctive of Plecotus. In 1864, Harrison Allen used Synotus 
of Keyserling and Blasius for the American bat, but in the following 
year he erected for it the new genus Corynorhinus, by which it con- 
tinues to be known, although Dobson in his Catalogue of Chiroptera 
in the British Museum (1878) took the more conservative course of 
regarding it as a subgenus of Plecotus. The dental formula — 12 a 
ct, pm =, m a3 = 36—is the same in both genera and shows 
but slight numerical reduction over that of Myotis, in the presence of 
two in place of three upper premolars on each side. In view of this 
somewhat primitive or unreduced tooth formula it is perhaps less 
surprising to find among the many specimens examined a single-one 
with three upper incisors. This condition is perhaps to be considered 
reversionary to the more primitive state in which the full number of 
three upper incisors characteristic of placental mammals, is present. 
It has been generally assumed that it is the innermost upper incisor 
that was the first to be lost in all bats with two incisors, partly be- 
cause of the “ correspondence of the two upper teeth with th two outer 
of the lower jaw when the maximum set is present, and also, even more 
strongly, by the general tendency throughout the group for the pre- 
maxillaries to become reduced, particularly along the inner edge”’ 
which would “inevitably result in eliminating that part of the bone 
in which the first incisor grows” (Miller, 1907, p. 27). Andersen 
(1912, p. xxiv) without going further into the matter, asserts, however, 
