34 



Merriam — Geogvapliic D!drU>utio)i of Life. 



families to which they respectively l)elong. In explanation of 

 this extended range it is found that these genera inhabited North 

 America in })re-glacial times and as a consequence have l^ecome 

 acclimatized to a wider range of climatic conditions. The semi- 

 Tropical belt of Florida is not known to possess any tropical 

 mammals except bats and a large indigenous mouse (Sitomys 

 marropiisy^, Ijut it has not been ex]:)lored by experienced mam- 

 mal collectors. Still, its recent origin and complete isolation 

 from other tropical areas would indicate the absence of ter- 

 restrial species derived from the south. At the same time it is 

 known to be rich in tropical plants, land shells, insects, and birds, 

 as is shown in another part of the present paper (see pp. 51-53). 

 It contains 9 genera of tropical birds, namely, Zenaida, Gentr>/(/nii., 

 Sfarncenas, RostrJiamus, Polijborus, Crotophaga, Euctheia, CaUlcheli- 

 dou, and Ckereha. 



The following 62 genera of mammals Ijelong to the North 

 American Tropical Region. The nine preceded by the letter S 

 enter the southern United States, which they penetrate varying 

 distances. Nyciinomas and Otoptervs inhabit the Lower Sonoran 

 Zone in common Avith the Tropical ; Didelphis pushes completely 

 through the humid division of the Sonoran Region ; and Felis 

 and Procyon enter the lower edge of the Boreal. 



North AmericAxX Tropical Genera. 



Cliironeotes 

 S' Didelphis 



Bradypus 



Chola'pus 



IMyrniccophaga 



Tunmudua 



Cycloturas 

 >S' Tatiisia 

 8 Dicotylcs 



Elasnioguatlius 



Capromys 



Plagiodontia 



Echinoinys 



Synetlieres 



Dasyprocta 



Coelogenys 



S Felis 

 »S' Procyon 



Bassaricyon 

 S Nasua 



Cercoleptes 



(Jalictis 



Solenodon 



Natalus 



Rhynchonyctcris 



Saccopteryx 



Diclidurus 



No(;tilio 

 S Molossus 

 S Nyctinomus 



C'hilonycteris 



Morniops 



Lonchorhina 



tS Utopterus 

 Vampyrus 

 Micronycteris 



• Traeliyops 

 I'hyllostoina 

 Million 

 Hemiderma 

 (ilossopliaga 

 l*liyIlonycteris 

 Monophylla 

 Leptonycteris 

 Glossonycteris 

 Chteronycteris 

 Artibeus 

 Vampyrops 



*Des('ri1)ed by tlic wiiterns Ilcxpcrodiijii indcrajtiis in N. Am. Fauna, No. 

 4, Oct., IS'K), J). .5:',. 



