734 MR. G. E. DOBSON ON THE MOLOSSI. [Nov. 7, 



21. Nyctinomus acetabulosus. 



Molossus acetabulosus, Commerson, MS. Fide Peters, Monatsb. 

 Akad. Berl. 1869, p. 402. 



Nyctinomus acetabulosus, Desmarest, Mammalogie, p. 1 1 7 (1820). 

 Nyctinomus natalensis, Smith, Zoolog. S. Africa, pi. 49. 

 Nyctinomus {Mormopterus) jugularis, Peters, P. Z. S. 1 865, p. 468. 



Ears quite separate, arising from the sides of the forehead at a 

 short distance above and in front of the eye ; the inner margin of 

 the ear-conch slightly convex for two thirds its length, abruptly con- 

 cave in upper third, so that the upper extremity of the ear is attenu- 

 ated, and the subacute tip projects forwards and inwards, instead of 

 backwards and outwards, as in most species of Bats ; outer margin of 

 the conch forming almost a straight line from the tip to its termi- 

 nation near the angle of the mouth, interrupted only by a slight 

 emargination opposite the middle of the tragus, indicating the com- 

 mencement of the antitragus ; tragus nearly as broad as high, irre- 

 gularly triangular, with a truncated vertical angle. Muzzle flat, ex- 

 tremity projecting considerably beyond the lower lip ; sides of the 

 upper lip with short ill-defined vertical wrinkles. In the male a large 

 glandular sac in the centre of the inferior surface of the neck, in the 

 female rudimentary. 



Wings from the distal third of the tibiae ; the fifth toe not so much 

 thickened as the first. 



Fur dark reddish brown above, somewhat paler beneath. Upper 

 incisors separate from the canines and also from each other ; lower 

 incisors small, slender, bifid, crowded ; the second incisor on each 

 side slightly overlapped by the margins of the first and third ; canines 

 without basal cusps ; the single upper premolar separated by a narrow 

 interval from the canine, with a projecting base internally, which is 

 concave behind and anteriorly develops an acute cusp ; first lower 

 premolar unicuspidate, equal to three fourths the second in vertical 

 extent. 



Length (of an adult J): head and body l" - 9 ; tail 1""7, tail 

 free from membrane "*6 ; head 0"'75 ; ear 0"'6, tragus 0""15; 

 forearm 1"*55 ; thumb 0"*25; second finger — metacarp. l"'5, 1st 

 ph. 0"*6, 2nd ph. 0"'7 ; third finger — metacarp. 1"'5, 1st ph. 0" - 5, 

 2nd ph. 0"*4 ; fourth finger — metacarp. 1 "* 1 5, 1st ph. 0" - 4, 2nd ph. 

 0"-2 ; tibia 0"-4 ; foot and claws 0"-35. 



Hab. S.E. Africa (Natal) ; Madagascar ; Bourbon ; Mauritius. 



The three last-described species, N. norfolcensis, N. albiventer, 

 and N. acetabulosus, differ from all the other species of the genus 

 in the relative lengths of the metacarpal bones of the second and 

 fourth fingers, resembling rather, in this respect, the species of the 

 subgenus Myopterus (gen. Molossus). In all other species of Nyc- 

 tinomus the metacarpal bone of the second finger is double the 

 length of that of the fourth ; in these three species, and in Myop- 

 terus, it is but one half longer. These species also agree together 

 in the form of the tragus (in which they also differ from all other 



