20 NORTH AMERICAN liAT^S J I. ALLEN. 



as a result lor the ►second bone to lie- in Irout of tlie third and for tlio 

 fifth to lie ill front of the fourth, is a notable feature in the nianus of. 

 the bat. Minor differences are seen in the relative len.nths of the bones. 

 They are shortest in pteropines and rhinolophines. The second meta- 

 carpal is usually slightly shorter than the others, but in Tlipposideros 

 it is much shorter. The tifth metacarpal boiu.' is a[»t to be the largest, 

 as in Ptcropiidj but in Jlippo.sidcro.s and in the moh)ssines it is the short- 

 est. In the j2froup last named and the related genus Atalapha the bones 

 are marked by i>roo\'es for the powerful metacarp()-])halangeal tlexor.v. 

 The third metacari)al bone is conniionly tlie lar<;est, the fifth tlu^ shortest, 

 the fourtli l)ein.<;- intermediate, yet in Noith American species of Fcs- 

 2>(t////o tlie fourtli bone, beini;- sliglitly shorter tlian the fifth, is some- 

 times an indi\idual varial ion. M((/((tl<riii(( is remarkabU; for luiving' the 

 above order leversed — the liffh metacarital is the largest and the third 

 is the shortest. Viewed as a whole tlie manus, notwithstanding its 

 enormous h>ngitudinal de\elopment in the third, fourth, and fifth ele- 

 ments, is singularly unimportant in the first and second. The second, 

 however, while unsui)ported by elongated phalanges, has strong archi- 

 tectural functions at the line of its union with the carpus. 



The phalanges present few points of contrast. They are uniformly 

 elongated rods. As a rule the second digit imssesses a single rudi- 

 mentary ])halanx Avhich may be free or semianchylised to the metacar- 

 pus. The highest degree of develoinnent is attained in the pteropines 

 and in the genus Rhinopomd, the former having three and the latter 

 two idialauges. In the pteroi)ines the third is ordinarily furnished with 

 a claw. They vary greatly in the range of motion, those of the second 

 and fifth digits being the least mobile; in their relative lengths in the 

 pteropines and the genera. Xoctilio and Mhiiopterus, these forms being 

 remarkable for the degrees present of lateral and dorsal flexion. It 

 has been noted on p. — that the disposition and relative sizes of the 

 phalanges vary in the scurrying and pendant forms. In the position 

 of flight the row of first phalanges is flexed doM-nward, but the row 

 of second phalanges is at the same time deflected laterally; /. c. to- 

 ward the body. In the position of rest the parts either remain axially 

 disposed or the row of the tirst phalanges is laterally or dorsally flexed, 

 as in the molossines and emballanourines. Tlie terminal cartilages are 

 apparently absent in i)teroi)ines and rhinolophines. When present they 

 remain in axial line with the i)halanges, as in idiyllostomines (excepting 

 Vam2)yn(-s), or they are deflected from that line, as in vespertilionines 

 and molossines. These little rods appear to be indices of the amount and 

 direction of strain to which tlie membranes are subjected, and point, 

 therefore, to distinctions in methods of flight. It may be said that 

 they are absent, or, if present, axially disposed in the broad-winged 

 forms, but are deflected in the narrow winged. In vesi)ertilionines and 

 molossines (excepting Kcrirouhf (.") -Mxd Aiitrozoii.s) the tifth digit is i)ro- 

 yided with^u accessory cartilage, wliich lies to the outer side of the 



