NATURAL SCIENCES OF PHILADELPHIA. 175 



C. TOWNSENDI. 



Head length' of body. Upper lip slightly tumid on sides of face, a line of 

 delicate hairs pendant. Excrescences sparsely haired ; tuberosities swollen 

 at base, bulging, outline obscure iuferiorly. Nostrils terminal, of an irregu- 

 lar trilobed shape ; external lateral angle obtuse, edges everted, with internal 

 inferior border rimmed. Chin with a wide triangular mentum. Ears with 

 internal fold one-fourth width of auricle, sparingly dotted with hair. Inner lip 

 to external basal lobe convex, much longer than high. Antitragus inconspicu- 

 ous. Tragus nearly half the height of auricle ; internal border thickened, 

 and slightly haired ; exterior basal lobe indistinctly quadrangular, wider 

 than long, and somewhat flattened externally, border convex ; central inci- 

 sions of upper jaw almost unicuspid.* 



Fur long and silky, on back less distinctly bi-colored than in the preceding 

 species, verging in some individuals to unicolor. The tips are of a darkish 

 brown mixed with grey, verging to the style seen in macrotis. The fur of the 

 belly is also blackish at base, with occasionally a ferruginous tinge ; the tips 

 are of two kinds, either a whitish hue, as in macrotis, or of an indistinct yel- 

 lowish brown. 



The points mentioned in the above descriptions with reference to the " in- 

 ternal basal lobe" and "inter-auricular membrane," may need explanation. 

 A simple auricle is seen in V. subulatus with a clearly defined internal 

 border and basal lobe. In Plecotus, Barbastellus and Synotus a crescentic 

 fold of membrane is seen at basal region of internal portion of auricle, 

 which is evidently homologous with the free lobe of the simple auricle. 

 But surrounding and extending upwards from it along the inner border .is 

 a membranous fold, which renders the true outline obscure. Such growths 

 I consider to be appendages to the auricle, and, while complicating the 

 detail of structure, in no Fay affect the plan. Should these folds meet 

 across the head, there woulcrbe formed an "inter-auricular membrane ;" this 

 may be complete, (that is, extending the entire length of auricles), as in some 

 genera of Noctilionida? and Megadertnatidas ; or it may be rudimentary, as in 

 the above genera. In the latter class the appendages are quite largely de- 

 veloped, though not touching ; and in this connection they may be considered 

 to be rudiments of an inter-auricular membrane. 



September 5 th. 

 The President, Dr. Bridges, in the Chair. 

 Fifteen members present. 



Dr. Leidy remarked, that of the two fishes from the Isle of Shoals, N. H., 

 presented this evening by Mr. W. M. Canby, one was of unusual interest. It 

 was a foetal Dog-fish, or Dog-shark, with the vitelline sac appended to its ab- 

 domen, which Mr. Canby had obtained, together with others, from a gravid 

 parent fish. Mr. C. had heard a dispute among several persons as to whether 

 the Dog-fish (Acanthias Americanus) laid eggs or brought forth living young, 

 and, having mentioned the matter to a fisherman, the latter said they brought 

 forth living young; and an opportunity offering shortly afterwards, proved it 

 by opening a gravid female and taking out the living young, of which the 

 specimen presented was one. 



The deaths of Sir Wm. Jackson Hooker, of England, and Mr. Charles 

 J. Wistar, of Germantown, correspondents of the Academy, were an- 

 nounced. 



* In Mon. loc cit. p. 66, read, on 7th line, leu " distinctly bifid at cutting edge." 



1865.] 



