VOL 



189; 



. XVI, 1 



wa. J 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



]>arts of tlu' bony iV.iiuowork, and the positions of the nerves, blood 

 vessels, and nuisele-faseieles are displayed. The paths of the nerves 

 and blood vessels constitute one system and may be spoken of together, 

 but the traeeuhi? and muscles are distinct from these and in some degree 

 from each other. As in the case of tlie relation which exists between 

 the skin and the bones, so in the arrangement of the parts just named 

 the degrees of strain to which the wing is subjected account in the main 

 for the ditference in the various genera. The muscle-fascicles are most 

 numerous in the membrane near the body, and are better developed in 

 the narrow-pointed Avinged forms, such as Molossi and Atahipha, than 

 in the broad, parachute-like forms. The muscle element in the wing is 

 especially weak in the Pteropida% E,hinoh)phid:e, and Vespertiliouidic. 



The fibrous lines which extend across the membranes are not without 

 system. Many of them are excessively attenuated tendons; such, for 

 example, are the tibres of the palmar fascia, already mentioned. Others 

 are the fibres which connect the Joints of digits ; more of them yet ap- 

 pear to be parts of a true derm. The nerves and blood vessels pursue 

 the same c(mrscs. Since the directions of nerves are of more impor- 

 tance in morphological study than the vessels, the former will be alone 

 named. In each interdigital space a nerve tends to enter at its proximal 

 end and, dividing into two branches, incline along the sides of the op- 

 posed metacarpal bones. The departures from this plan are numerous, 

 and are so constant in groups of generic and even specific limitation 

 that they constitute a valuable addition to diagnoses. 



The wing membrane, when expanded, exhibits dittereuces in the width 

 of the interdigital spaces. These differences relate in an intimate man- 

 ner with the behavior of the jiarts in fiight, and consequently with 

 Labit. The subjoined table indicates some of these distinctions: 



Manal (pteral) fonnitliv of the widths of second, third, and fourth intersjxtees. 



Species. 



Lophostoma 



Scliizostoina 



Mai'i-otus 



Di'smodus 



Vaiiipyrops 



Chiloiiycteris 



Heniidemia 



Vanipyrns 



Loiii'hoglossa 



Monopliylliia 



Artibeiis 



I'>i:uliypliylla 



Moiiuops 



I'hvUostonia 



KliyiKlioiiy<'teris 



CyllDIltlTHS * 



\'csinMtilio t 



Epoiiiopliorus J.. 



Kliinopoiua 



Molossus § 



Noctilio 



Pteropusll 



II. 



.3 

 1.J 



l(i 



:! 

 :i 



4 

 3 

 3 

 4 



III. 



mm. 

 17 

 16 

 15 

 "Jl 

 17 

 15 

 20 

 41 

 19 

 17 

 ■21 



■ . 25 

 16 

 29 

 16 

 18 

 II 

 21 

 13 



13 

 17 



Difl'erence 



between 



III and IV. 



7 

 10 

 10 

 12 

 9-12 

 12 

 12 

 14 

 18 

 18 

 19 

 45 

 9 

 9 

 10 

 11 

 17 

 30 

 45 

 52 



*C. niar^iuatua. 

 t V. niiinnus. 



I E. IVanqiieti. 

 §M. rut'iis. 



1 1'. edwardsii. 



