NYCTINOMUS TENUIS. 



The characters of this singular genus among the VespertilionidEe, were first 

 defined by M. Geofiroy, in the Memoirs of Natural History, which form part of the 

 description of Egypt, being the collection of observations which were made in that 

 country during the Expedition' of the French army. In proposing Nyctinomus as a 

 genuSj M. Geofiroy details the distinguishing characters in a copious manner, but with 

 his usual perspicuity and elegance. In describing a new species from the Island of 

 Java, it has appeared useful to me, to premise the substance of M. GeofFroy's obser- 

 vations, founded on a consideration of all the species previovisly known. 



M. GeofFroy commences by stating that no combination of characters departs 

 farther from the common type of the Mammalia. The Nyctinomi, he proceeds, 

 have the flat nose, and hanging hp of the mastiff, but in an excessive degree. 

 The head appears as if crushed under the weight, and is in a great measure concealed 

 by the amphtude of the ears. These are not simply vestibules to the auditory tube ; 

 but they meet each other on the crown of the head, and, extending over the fore- 

 head, are prolonged to the region of the intermaxillary bone, and by this arrange- 

 ment they cover the cranium entirely. By their excessive development, and by 

 means of a fold of the inferior lobe, they afford a peculiar protection to the eye . 

 they apply themselves over this organ, and thus answer the purpose of a second 

 eyelid. To keep the ears elevated, and to cause them, in one point of view, to 

 constitute a concha before the meatus auditorius, and in another to afford to the 

 eyes their proper axis of vision, requires the contraction of all the integuments of 

 the head. The entrance of the ear is provided with that enlargement of the tragus 

 which is peculiar to the Vespertilionidge, and which is termed by the French 

 naturalists oreillon, and by Illiger, the operculum. The cerebral case is broad and 

 depressed, and the flatness of the head is not merely an appearance produced by the 

 disposition of the ears, but it is real. The skull is abruptly truncated behind, and 

 the foramen occipitale is remarkable on account of its excessive size. The nostrils 

 would appear extremely simple, were it not on account of the upper lips, which 

 are cleft, and passing backward, lose themselves on the cartilages of the nose, which 

 have the form of a mufl. The upper lips are wrinkled with fi-om five to eight 

 transverse folds on each side ; and they are rendered stiU more rugose by means of 

 warts dispersed about them and about the ears. The olfactory openings are lateral 

 and distant, they are at the same time circular, and in consequence of the thickness 

 of the cartilage, they do not appear to possess the capacity of alternately opening 

 and shutting themselves. This is, notwithstanding, the case with most of the other 

 VespertUionidee. 



M. Geoffroy proceeds to detail a remarkable peculiarity in this genus, by means 



