8 BULLETIN 43, UNITED STATES NATIONAL MUSEUM. 



Manal (pteral) fonnula^ of the widtf.. of .second, third, and fourth interspace.. 



Lophostoma 



Schizostoiua 



Macrotus 



Desmodiis 



Vampyrops . 



C'hiloiiycteris 



Heiuiderrua 



Vampyrus 



Louchoglossa 



Monophyllus 



Artibeus 



Urachyphylla 

 Mormitps. . 

 Pliyllostom 

 EhynchoDycteris 

 Cynoptenis ' 

 Vespertilio t 

 Epoinoi>liorus * 

 Kliinopoma 



Molo8.SU8§ 



Noctilio. 

 Pteropus 



* C. marginatus. 

 t V. muiiuus. 



J E franqiieti. 

 §.M. rufus. 



P. edwardsii. 



This list is selected in tbe mail, for comparison in members of a sin 

 gle family y,., tbe Phyllostomida-. The last eisht forms are from fai r 

 lies other than the one first named 



It is believed that these distinctions may be conveniently inclnded 

 m the characteristic proportions of bats. 



flex'ed"iM''pi!!!u 't'""", '" "-'""'"'* '" ^««PertiIionida., bnt partially 

 flexed m hylostomidie (excepting Besmodu.^- and J,ip,u,ll4 and in 

 Plecot. The degree of inclosure of the thumb in the mnnbrane a 

 swers to the amplitude of the membranes generally ami when ext^ns^e 

 tends to draw the thumb slightly toward the palm, the space brtZt 

 tlie^thnnd, and index finger being moderately occupie.1 by a skin eM.an 



It is a teiidency under certain conditions for all growth processes to 

 dominate functions other than those which are e.4e„tial t,, theh ow n 



fold of skm between the limbs is seen in the liatrachia. In the water 



rrinik'T?- ■'"' ":'S'^'"'^'«» --extending along the sidfo 

 the trunk This is contnuious along the hinder b,u-der of the anterior 

 ex remity (well developed in Ji„„j«„,<„ and reaches as far as the 

 of the fifth digit. This fold is supplied by the ulnar nerve, which ,p 

 pears to be in its earliest expression a nerve for the sk f the poste- 

 rior border of the forearm, of the fifth digit, and the muscles lb,rd in 

 these regions. The phenomena of a. fold of skin extending betwee the 

 oes IS one already familiar, so that the general plan of thc^skhcn' ai ise 

 m a creature so low as the Menoj,o,„„ prefigures that of so hi..|,lv s e 

 cia .zed a form as the bat without violence and withoutleavin; i, g,e 

 line obscured. Diflerence of degree and not of kind separate: them. 



