132 BULLETIN 43, UNITED STATES NATIONAL MUSEUM. 



By the number of upper premolars and incisors J^ycticejus approxi- 

 mates Seotophilus, Rhogeessa, and Atalapha. Coues and Yarrow, indeed, 

 (Wheeler's Expedition, 1875), place it with the genus last named. Mr. 

 Oldfield Thomas is inclined to place it witli Yeiiperugo (see infra). In 

 my opinion the structural peculiarities are of a character which warrant 

 a separate generic diagnosis. The nearest ally of Nycticejm is RJiogd'ssa, 

 which may be said to represent it in the South American fauna. In the 

 details of the molars and of the wing membranes it is iinlike any of the 

 forms of our fauna, l)ut most resembles Adelonycteris and Vesper ugo. 

 Until Peters identified the ScotopMIus of Leech, -iV</c'fi«y'*^s w\as tliought 

 to be distributed throughout the tropical belt of the Old World. It 

 is now held to be confined to the Avarm southern parts of the United 

 States and Central America. 



O. Thomas (quoted in Mammals Living- and Plxtinct, Flower and 

 Lyddeker, 1891,) credits Xyctk-ejus to Scotophilus. I can not agree 

 •with this determination. In Scotophilus the last upper molar is like Ata- 

 lapha; in Nycticejus it is like Yespcrngo. The details of the lower 

 molars are absolutely different. The hypoconidin Scotophilus is small, 

 narrow and blunt; the triangle composed of blunt cusps with shallow 

 interspaces. The hypoconid is large, larger than the triangle (which 

 is compressed from behind forward as in Xyctinomus), and has high 

 aciculate cusps. The character of elbow-movement is distinct in the 

 two forms. In Scotophilus the inner radial facet on the humerus is 

 weak, scarcely at all concave. The joint is strengthened by a bold, 

 trenchant epitrocldea. In Xycticejus the inner radial facet on the 

 humerus is deeply concave and sharply defined, thus strengthening the 

 joint, while the epitrochlea is small and feeble. The palate is prolonged 

 backward markedly in Scotophilus, but scarcely at all in Nycticejus. 



1. Nycticejus humeralis O. Thomas. (Plates xxii, xxiii.) 



Nycticejus crejyiittcularis Lieconte Cuv. An. Kingd. (McMurtiie's ed.), 1831, 432 j Jas. 



Lecoiite, Acad. Nat. Sci. Phila., 1855, 433; H. Allen, Monog. N. A. Bats, 1864, 



12, figs. 9-11. 

 VespertUio creeks F. Cuv., Nouv. Annal. du Mus., Paris, i, 1832, 18. 

 VespertUio aenobarbus Temmiuck, Monog. Mam., 1835-'41, 247, PI. 58, Fig. 4, vide 



Peters, MB. Akad. Berk, 1866, 681. 

 res2)en(S cubanns Gundlacb, MB. Akad. Berk, 1866, 681. 

 Nycticejus humeraHs O. Thomas. Auu. & Mag. N. H. vii, ISiU, 528. 



In the monograph of 1861 I queried whether or not iV. humeralis, 

 Eafinesque, was the same as W. crepuscular is. I have since concluded 

 that they are the same and, therefore, agree with Mr. Oldfield Thomas 

 in accepting this name. 



Diagnosis. — The diagnosis of the single species, that of the genus. 



Description. — Auricle small, shorter than the head, the portion above 

 the head oval; outer border scarcely concave, tip obtuse. Internal 

 basal lobe bold, thick, interiorly forming a minute pendant point; an- 

 terior border abruiJtly convex ; it does not touch the head, but is raised 



