Proceedings of the Scientific Meetings of the Zoological Society of London 1875

Page 432

370 MR. G. E. DOBSON ON THE GENUS SCOTOPHILUS. [May 4, bases ; upper premolar large, exceeding the molars in vertical ex­tent, and quite close to the canine : last upper molar consisting of a transverse plate only; first lower premolar small, crushed in between the canine and second premolar, which exceeds the molars in vertical extent. All the molar teeth very strong, with acute cusps. Distribution.-Africa, Asia, and Australia. In Africa probably not south of Port Natal: in Asia confined to the warmer parts, ex­tending from Afghanistan to Southern China and the Philippines: in Australia probably extending throughout the whole country. This genus, though difficult to define, and approaching Vesperugo, Keys. & Bias., in many points, especially through certain species of that genus, contains a very natural group of Bats of very wide dis­tribution (as above described) throughout the tropical and sub­tropical regions of the Eastern Hemisphere. They are distinguished specially by possessing a single pair of upper incisors separated by a wide space and placed close to the canines; by the small transverse first lower premolar crushed in between the approximated canine and second premolar, yet standing in the tooth-row; and, generally, by their short, conical, naked muzzle, and rather short and narrow ears ; by their heavy bodies and strong limbs with remarkably thick and nearly naked leathery membranes; and by their short fur, gene­rally olive- or chestnut-brown above, and yellowish or reddish white beneath. Owing to the wide distribution and variableness in size and colour of the species of this genus, many different names have been given to the same species*; and this variableness and a close external resemblance between different species inhabiting distant countries has caused considerable difficulty in determining species from descriptions either very imperfect or based upon general characters only, such as the colour of the fur and measurements. It is evident, therefore, that if some characters be found by which the species may be divided into subordinate groups or subgenera, the difficulty of determining the different species will be much lessened. Such characters I have found in the form of the internal basal lobe of the ear and in that of the tragus. The species may therefore be arranged as follows :- A. Internal basal lobe of ear angular, inferior mar­gin straight, forming with the ascending mar­gin almost a right angle: tragus with a narrow prominent ridge passing across its front surface from the base of its inner margin (Scotophilus.) a. Upper incisors close to canines; premaxillary bones very narrow, leaving a wide space be­tween them in front, nasal opening very large. a. Cingulum of the upper incisors very nar­row S. temminckii, Horsf. (3. Cingulum of the upper incisors forming a broad horizontal shoulder behind, scarcely raised above the level of the g u m S. borbonicus, Geoff. * E. g. Scotophilus temminckii, Horsf., = Vespertilio belangeri, Is. Geoff., = Vespertilio noctulinus, Is. Geoff., = Vespertilio castaneus, Gray, =Nycticejas luteus, Blyth, =Nycticejusflaveolus, Blyth.