VESPERTILIO CHILOENSIS. PLATE III. _V. fuscus: auribus mediocribus; trago elongato, angusto, apicem versus attenuato; fronte concavo; rostro obtuso; caudâ ad apicem extremum liberâ._ DESCRIPTION.—In size and colouring, this Bat very closely resembles the _Vespertilio Pipistrellus_ of Europe; the wings, however, are considerably broader in proportion; the antibrachium, tibia, and tail, are each of them longer; the tragus of the ear is also longer, and narrower. The muzzle is short and obtuse, and furnished on each side with numerous hairs, which, when compared with those of other parts, are of a more harsh nature. The nose is naked at the apex. The forehead is concave. The ears are narrow, and somewhat pointed, emarginated externally, and have about four transverse rugæ: the tragus is elongated, narrow, and pointed, and has the outer margin very obscurely crenulated. On the chin there is a small wart, from which spring several stiffish hairs. The tail is about equal to the body in length, and has the extreme tip free. The fur is moderately long, and of an uniform rich brown colour, and extends on to the base of the interfemoral membrane above and below; the remainder of this membrane is bare, and, together with that of the wings, of a black colour. In. Lines. Length of the head and body 1 8 the tail 1 3½ Expanse the wings of 8 3 Length of the ear 0 5½ the tragus 0 3⅓ the antibrachium 1 5½ the thumb (claw included) 0 2½ the tibia 0 6¾ Habitat, Chiloe. (_January._) “This specimen was given me by Lieut. Sulivan, who obtained it amongst the islets on the Eastern side of Chiloe. It is not, I believe, common, nor do the humid and impervious forests of that island appear a congenial habitation for members of this family. It must, however, be observed, that even in Tierra del Fuego, where the climate is still less hospitable, and where the number of insects is surprisingly small, I saw one of these animals on the wing.” D. FAMILY—NOCTILIONIDÆ. DYSOPES NASUTUS. Molossus nasutus _Spix_, Simiarum et Vespertilionum. Braziliensium species novæ. Nyctinomus Braziliensis.—_Geoffroy_, Annales des Sciences Naturelles, tom. i. p. 337. pl. 22.