92 ZOOLOGY. 



They are collectively distinguished from any of the foregoing Vespertilionidce 

 by the presence of four instead of two upper incisors. They fall in four sub- 

 genera, according to peculiarities of the molar dentition. The single species of 



Vesverus has molars - , 32 teeth in all. The two or three species of Vesper ugo 

 5-5 



have molars -. 34 teeth in all. The species of Vesperides has ~. The 

 5-5 o o 



rt ri 



several species of true Vespertilio have molars -'. 38 teeth in all. The 



o-b 



species of Vesperus and Vespemgo are more nearly related to each other than 

 they are to those of typical Vespertilio, and are often together separated 

 generically from the last named; but, as Dr. Allen has observed, in so separat- 

 ing them the differences are difficult to describe. Vesperus and Vespemgo 

 have heavier wing-membranes, and thicker, more leathery, ears, developing 

 in width rather than in height : Vespertilio contains more delicately organized 

 species, with thin wings and ears. " The difference in their facial expression 

 might be compared to that between a mastiff and a terrier dog : the former 

 is massive, with broad head, pendulous lips, and wide ears ; the latter is 

 more slender, with a narrower face, and delicate and upright ears." The 

 skull in Vespertilio is lighter, with narrower rostrum, more concave frontal 

 outline, and more inflated cranial pai't. 



VESPERTILIO (VESPEKUS) FUSCUS, Beauv. 

 Carolina Brown Bat. 



Vespertilio fuscus, PALISOT DE BEAUVOIS, Oat. Penle's Mas., 17'JO, 14. LECONTE, 



Proc. Pliihi. Acad., 1S55, 434. 

 Scotophilus fuscus, ALLEN, Mouog., 31. 



Vespertilio carolliiensls, GEOFFROY ST. HILAIRE, Ann. du Mus., 1800, viii, 193, ]>1. 

 xlvii, f. 7. HAUL., Fn. Am., 1825, !). GODM., Am. Nat. Hist., i, 1831, 

 07. LE(J., McMurt, Ouv., i, 1831, 431. OOOP., Ann. Lye. N. Y., iv, 1S37, 

 60. DEKAY, N. Y. Fii., i, 1842, 10, pi. 2, f. 1. DESM., Mamm., i, 1820, 130. 

 TEMM., Mon., ii, 1835, 237. LEO., Proc. Acad. Nat. Sci. Phila,, 1855, 434. 

 WAGN., Suppl. Scurcb., v, 1855, 753. WOODH , Sitgr. Kep. Zniii and Ool. 

 Eiv., 1854, p. 43. 



Scotophilus carolinvnain, ALLEN, Monog., 28. 



V r c8pcrtUio arcuatus, SAY, Long's Expcd., 1823, 107. 



Venpertilio phaiops and 1 Eptexicus melanops, ItAFiNEsyun, Am. .Month, ^lag., 1818, 

 445 (wee Temin.). LEG., Proc. Acad. Nat, Sci. Phila,., 1S55, I3l._ 

 Suppl. Sclnvb., 1855, 750. 



