10 BULLETIN 43, UNITED STATES NATIONAL MUSEUM. 



that of the iuterual border, while the posterior i)art is marked, if 

 marked at all, by couspicuous transverse lines or striae. The hair 

 when it extends upward on the ear from the crown is usually of the 

 color and character of that of the crown, while that of the posterior is 

 of the color and character of that of the neck. 



The fraf/Hfi varies exceedingly in form. The following terms are em- 

 ployed in its description, viz, tlie hmer and outer border, the ti2), the 

 notch, which is near the base of the outer border, and the basal lobe, 

 which lies below the notch. The tragus is said to be absent in Ptero- 

 pidie and Ehinolophidie, but in some examples of the family last named 

 arudimental tragus can be discerned. The tragus always arises from 

 the ridge which lies iu front of the auditory meatus and connects the 

 inner and outer auricular borders. It is of interest to observe that 

 while this connection with the borders is imperfectly defined in most 

 bats that in the recently discovered Endertna it is markedly so united 

 and tends to constrict the basal parts of the enorm :*us auricle. 



Not only is this the case, but the ears are often united by a band 

 {inter auricular membrane) which extends obliquely forward. In Cory- 

 norhinus and Macrotus it is on the face, and in Promops perotis reaches 

 quite to the snout. 



In illustration of the value of the ear in classification the following 

 table is drawn up from the members of the bats described in this 

 memoir. 



Phyllostomidic. — External ear without internal basal lobe. External 

 ridge rudimental or absent. External basal lobe not marginal, but lies 

 well within the large second scallop, which is continued well in front; 

 tragus prorect, coarsely crenulate or spinose on outer border, 



Molossi. — Ear without internal basal lobe. Internal ridge produced 

 forming a "keel." External ridge marginal, produced, bounding exter- 

 nal basal lobe. External basal notch open, i. e., not covered by lower 

 scallop ; tragus rudimental. 



Vesper tUionida\ — Ear with internal basal lobe. Internal and exter- 

 nal ridges rudimental, not produced. External basal lobe marginal 

 (except Plecoti), not touching external basal ridge. External basal 

 notch occupied by produced lower scallop. Tragus obscurely crenu- 

 late on outer border, or smooth. 



SECONDARY SKIN DEVELOPMENTS. 



At the muzzle the skin folds are median and lateral. The margins 

 of the nostrils expand above and at the outer side while they are sepa- 

 rated by a groove or a ridge in the middle line, as is seen in Brachy- 

 phylla and Nyctinomus. Or the two lines of perinarial expansion may 

 meet below in the space between the nostrils and the lip to form a 

 swollen ridge as in Glossophaya or a lappet as in most Yampyri, while 

 the internarial ridge is continuous with a vertical leaflet. This is the 



