286 PROCEEDINGS OP THE ACADEMY OP 



Measurements 7841. 



Height of auricle 6" Length of longest finger I'-ll" 



" tragus 3" " thumb 2" 



Length of head 7" " tibia 5" 



" body 10" " foot 2 \" 



" tail L'- 2' Expanse C- 7" 

 " forearm 1' 1" 



Two individuals,^ and 5. Nos. 7841, 7842, Museum of Smithsonian 

 Institution. Alcohol. 



Tres Marias, Mexico. Col. Grayson. 



R. tumida, n. s. 



Fur above bi-colored ; basal two-thirds pale yellow, apical third dark fawn, 

 less distinctly bi-colored towards loins, where it becomes woolly. Beneath as 

 above, fawnish toward the sides. Specimen deficient in fur at loins and wing 

 membranes. It is probable that the membranes at base of tail and sides of body 

 were clothed with fur. Snout tumid, not truncate ; nostrils circular ; sides 

 of face enlarged by large oblong swellings-; wart above eye, none under chin ; 

 lower lip tumid, free from gum ; lips not whiskered. Skull with nasal groove 

 less expressed, inner wall orbit less convex than N. parvtdus ; side of face 

 over infra-orbital foramen slightly swollen. Dentition as in preceding spe- 

 cies ; superior incisors not bifid points probably worn off. 



Measurements. 

 Height of auricle 6" Length of longest fiDger 2". 3"' 



tragus 3" " thumb 2{" 



" head 7" " tibia 5" 



" body 12" '< foot 2" 



Length of tail 1" Expanse 10- 3" 



" fore arm 1-2" 



One individual, J*. No. 8195, Mus. of Smithsonian Institution. Alcohol. 

 Mirador, Mexico. Dr. Sartorius. 



This genus appears to connect the Noctilionidae with the present family : 

 with the former through Nyctinomus, with the latter through Nycticejus. The 

 circular nostrils, sub-truncate snout, the detail of inferior incisors, the angle 

 of lower jaw to Noctilionid?e ; the tapering face, marked median groove, taper- 

 ing tragus and pointed ear, number and general arrangement of teeth, extent 

 of hard palate, length of tail and attachment of wing membranes, to Ves- 

 pertilionidae.* 



It reminds one of Nycticejus and Lasiurus in the slightly tumid face (this is 

 more marked in B,. tumida) and the dentition ; while the shape and relative 

 length of the auricle and tragus, and the decurvation of nasal bones, recall 

 Vespertilio. 



* The value of the presence of one or more phalanges to the index finger, in the classification ef 

 this group, is not yet determined ; so the fact that this finger in Rhngeessa is made up of two pha- 

 langes has not been made a fe iture of the diagnosis. My attention has been recently directed to 

 this subject by remarks made by Prof. Peters (Monatsbericht. der Kbnig. Acad, der Wissenscbaft, 

 Berlin, Oct., 18(55), in his paper on the true position of Anlrozous, who, by the presence of two 

 phalanges to the index fiuger of Antrozous, would remove it from the position I assigned itthe 

 Vespertilionidas to the Megadermatidse: placing it in proximity with Nyctophilia. Butso far as I 

 have observed, the distal end of the first phalanx is always abrupt ; the interval between it and the 

 com our of second finger is membranous in Nyctinomus. but partially ossified, forming thus a second 

 phalanx in Lasiurus, Anlrozous, Vespertilio, Scotopliilvs, and Nycticejus. lam not acquainted with 

 Nyctophilus, but in Mtgaderma lyra the second joint is relatively no larger than in Lasiurus or 

 Scotophilus. while it is more marked than it is in Anlrozous. From reading Mr. Tome's description 

 of Nyctophilus (Proc. Zool^Joc, 1858, 25), I would.with Prof. Peters, approximate it to Antrozous, but 

 would agree with Mr. Tomes in considering Nyctophilus and its congeners as members of Vesper- 

 tilionidffl. Asecond phalanx exists in my new genus, while no such phalanx is seen in Nyctino- 

 vi us. 80 it w.ull appear, in absence of the observation that the um-phalangeal index finger is not 

 common to Noctiliouidae, that Shogeessa, is nearer Nycticejus than Nyctinomus. 



fAug. 



