2 NOHTll AMKiaCAN 15 ATS II. ALLI'.N. 



liiiytM's of skill (Imsiiijikc up the wiuj; iiM'iiilniiiK'. Tlicy iH'c (•(tiitiiiuous 

 tVoiii (lie l;ist. liiiucr niid Mic tliuml), oi' some adjai.'cMil surfiu'o, to the 

 sides of tlic body, tlio lu'ck (both abo\ c and bolow Mic ai'in and lorcaini), 

 and tlu'outor side ol" (lie postciior oxtrcinily. F.acli win^' mcinbiane 

 roaclu^a below the knoc and from this point, in varying degrees, to the 

 ankle and tlie foot . The si)a('e between the i)osterior extremities is also 

 oecnpied, as a rule, by two adjoined layers of iutegnnient wliieh eon- 

 stitiitcs the interfemoral membrane. This struetiire as opposed to the 

 above is less constant in form and dimensions, it may be guided by ;i 

 long tail (piite to its tip, it may allow the tip to project in dilVereiit de- 

 grees beyond its free margin, it may greatly exceed in size that of the 

 stunted tail, it may be delined as a hem alonii" the inner border of the 

 limbs, or it may be entirely absent. 



It follows from these statements that all bats are provided with a 

 back and a front skin-expanse from the sides of the body to the extremi- 

 ities in a constant manner, but from the tail to the posterior extremities 

 in an inconstant mann(^r, tlu> last named presenting modifications deter- 

 mined by degrees of outgrowth of the tail itself. 



The nuMubranes present many details with respect to the manner of 

 their attachment to the sides of the body and to the various parts of 

 the limbs. Interesting variations of i)lan are seen where the skin 

 crosses Joints. In the elbow joint, the skin may be attached entirely to 

 the epicondyle, so that the Joint lies (piite to the under side of the 

 -wing, as in the Afric.m fox-bat, /•.7><>'"<'/'/"""*'''.<>i' ^^ ''*''.V be attached 

 midway, namely, to the olecranon, as in many forms, but perhaps best 

 seen in tlie neotro|)ical American t^dccoptrri/.r; or it may be attached 

 eidircly to the epitrochlea, so that the Joint liesipiite on the npp«'r sur- 

 face of the wing, as in liliiiioloi)!!!^^ pcarsoxi and T<(j>h():oiis. At the 

 wrist distinctions are seen in tlie manner in which the tendons of the 

 ext(Misoi' carpi ulnaris and lU^xor carpi ulnaris are disposed at the angle 

 which is formed between the radius and the fifth metacari)al bone. 

 NN'licn tliis angle is mark(>d, and skin folds are ccmspicnous over the 

 len(h)ns named, a radionietacarpal pouch isdetined. Tiie knee always 

 lies on the upper surface of the membrane. It is most free in Macrotus 

 and least so in the Molossi.* The mend>rane attached to the ankle may 

 lie entirely to the pollical side of the joint, but is disposed to cross it 

 by an obli»iuc raised fold and be secured to the minimal, /. c, little toe 

 side. 



I have Ibund it conviMUiMit to employ a number of nanu's for tlu^ sub- 

 divisions of the dermal expanse. 



The membrane which extends from the sides of the trunk to include 

 the anterior extremity is the wing nu'mbrane ('*bat wing," patagium). 



The membrane between the legs is the interfemoral membrane (nro- 

 patagium). 



* 'riio jxroiin nainod tho Alolossi will lie luld in lliis cssav to ho distinct from the 

 _oi(iiii> of winch Kmhal Ion i( III 'if< tlit" I'cntral gcmis. 1 am of the opinion that these 

 alliances are distinct and co-tupial. 



