INTRODUCTIOX. 



I. General ckakacters of Mkgacjiiroptera. 



The prototype of tlio Chiroptera must have possessed all tlio 



mo.^t primitive features preserved by any living or extinct form of 



!Me.gachiroptera and Microchiroptera. Among its more important 



characters, therefore, must have been these : — 



Skull. — In general shape probably essentially like that of a 



liouscttus or Pteropiis, with the following differences : the bony 



palate was not produced backward behind the tooth-rows (compare 



Insectivora and Jlicrochiroptera generally) ; the infraorbital canal 



long {cf. the Notopteris section of Megachiroptera, and somo 



Microchiroptera); the postorbital processes undeveloped (as in the 



majority of Microchiroptera"); tlie facial portion of the skull not, 



or only inconspicuously, deflected against the basicranial axis (as 



in nearly all genera of the Epomopliorus and Crjnopiei'us sections 



of Megachiroptera). 



n .-.• T^ ,-^e ^ t,ui ^' i" — ° P' — p^ p' m' m= nv\ 

 Ventition. — Dental tormula probably .-^-^ *, 



I1I2I3CP1— P3P4m, ^2^3 



this being the completest formula found in any bat (i' may have 

 been ])resent, though lost in all known species) ; molar structure 

 typically " Insectivorous," as in Microchiroptera with unmodified 

 cheek-teeth. 



Fore-limbs and memhravcs. — Tuheratlum majus and miiuis of 

 humerus relativel}' small, the former not articulating with scapula 

 (cf. Megachiroptera and some primitive Microchiroptera) ; deltoid 

 crest of humerus weak (cf. Megachiroptera). Ulna not more 

 reduced than in Megachiroptera. Articular surfaces of the bones 

 of the hand (earpo-mstacarpal, metacarpo-phalangeal, and inter- 

 phalangeal joints) not more modified than in Megachiroptera ; 

 trapezium large (cf. Megachiroptera) ; second digit rclalively 

 independent of third, with three phalanges and a well-developed 

 claw (cf. Archcmpteropus f and typical Pteropodida). Wing-i 

 membranes from tlaiiks and inserted i)osteriorly on first toe. ' 



Tail. — Long and embedded in interfemoral (cf. ArcTiceopteropus, 



* On the liouiologies of the iiiissing premolars in Chiroptera, see Oldfielcl 

 Thouias. Ann. & Maj;. K. II. (8) i. p. 3i'j (1908). On the missing upper 

 incisor, K. Andersen, P. Z. S. 1908, p. 205. 



t On Aixhieopteropua traiisieus (Upper Oli^ocene, Monleviule, Italy) see 

 IMesfhinelli, Atti R. 1st. Veneto, Ixii. p. 1329, pi. is. (1903). Note on il3 

 wine-struolm-e, infra, p. ssxvii. 



I, 



