192 BEPORT — 1880. 



Thumb with an ill-developed claw, but the whole of the inferior surface 

 of its metacarpal and phalangeal bones supports a large flat horse-shoe- 

 shaped pad, more than 0"'2 inch in diameter, whereof the circular margin 

 is directed forwards and slightly notched in front. The feet have also 

 adhesive cushions, but while resembling those of the thumbs in structure 

 they differ in being much smaller. 



Metacarpal bone of the index finger nearly as long as that of the 

 index fiftger, but there are no distinct phalanges ; third finger with three 

 phalanges, whereof the first and second are nearly equal in length. 



The tail projects beyond the posterior margin of the interfemoral 

 membrane, as in Thyroptera tricolor, but to a much greater extent, the free 

 portion being nearly as long as the tibia ; calcaneum long, with a very 

 narrow lobe notched or toothed near the foot. 



As in T. tricolor, the toes are united as far as the base of the claws, 



and have each two phalanges, and the wing-membrane extends almost to 



the base of the claws. 



2—2 1—1 3—3 3-3 



Dentition :— inc. — -, c. — , pm. — , m. — . Upper incisors short, 



in pairs, placed close to the canines ; the outer incisor, on each side, small, 

 conical, and acutely pointed, but much larger than the inner one, which 

 lies close to it, and can hardly be discerned without a lens ; lower incisors 

 short and blunt, in the direction of the jaws ; first and second upper pre- 

 molars very short, the third exceeding the molars in vertical extent; 

 second lower premolar minute, in the tooth-row, the first premolar 

 slightly smaller than the third ; molars acutely tubercular, with W-shaped 

 cusps. 



Length (of the type, an adult male, in alcohol) : head and body 2"-3 

 inches, tail l"-9, tail free from membrane 0"-6, head 0"-85, ear l"-3, 

 trao-us 0"-25, forearm l"-85, thumb 0"-3, third finger (metacarp. l"-5, 

 lst°ph. 0"7, 2nd ph. 0"-75, 3rd ph. 0"-55), fifth finger (metacarp. l"-5, 

 1st ph. 0"-5, 2nd ph. 0"-5), tibia 0"-7, calcaneum 0"-6, foot 0"-3. 



Certain peculiarities in the structure of this very remarkable species 

 recall similar peculiarities in Thyropiera tricolor, and have evidently re- 

 sulted from adaptation to the same purposes. Thus in these two species 

 alone are the toes united to the base of the claws, and in them alone, 

 among all known species of bats (except the Phyllorhiniuce), have the toes 

 an equal number of phalanges ; they also, in the possession of a third 

 phalanx in the middle finger, differ from all the species of Vespertilionidce, 

 and from those of the allied families. This species, however, differs re- 

 markably from T. tricolor in the structure of the adhesive disks, in the 

 presence of a well-developed metacarpal bone of the second finger, in the 

 form of the head and ears, and in dentition, and must undoubtedly be con- 

 sidered the type of a distinct genus of Vespertilionidce. 



The adhesive cushions of the thumbs and feet are evidently less perfect 

 clinging organs than the corresponding parts in T. tricolor ; unlike them, 

 the thumb-pads are sessile, scarcely hollow on their inferior surface, and 

 evidently homologous in all respects to tho.se of Vespertigo pachypus ; but 

 the foot-pads differ from those of that species in being much smaller and 

 in this respect corresponding with T. tricolor. 



It is probable that this species (in common with the few other known 

 species of bats provided with such accessory clinging organs') uses the 

 ' See my paper ' On Peculiar Structures in the Feet of certain Species of Mam- 

 mals, &c.,' P.Z.S., 1876, p. 526, pi. Iv. 



