31G DR. KXUD ANDERSEX ON BATS. [Apr. 7, 



According to this avvangement thei-e ai"e two principal branches 

 of the genus : in the one, and more primitive, cnsp 7 of m^ is pro- 

 portionally small, in the other it is largel}' developed. The 

 former, as being the moi-e primitive, is qnite naturally but poorly 

 represented among recent species ; the latter is flourishing. Of 

 the lowest section (molars 4) of the primitive branch (small cusp 7) 

 no living species are known, but there are species with | molars 

 (glccHCUs, watsoni), and % molars (cuierexs, roseiibergi); the latter 

 species, rosenhergi, has attained an unusually high development 

 (not only loss of ni'' and m,„but also reduction of nrand m„). Of 

 the higher branch (large cusp 7) all sections are repi'esented by 

 recent species : 4 molars in concolor (peculiarly short-faced), 

 planirostris and kivsiitus, the two latter species very closely 

 allied ; -| in jamatcensis, otherwise differing in next to nothing 

 from planirostris ; % in quite a number of species (quadrivittatus, 

 toltecics, 2^fi'<-Votis, azteciis, turpis, nanus), among which turpis 

 and nanus mark the highest stage of development, in so far 

 as the rostrum has become unusually depressed and the palate 

 shortened. 



(b) Artibeiis planirostris and its races. — A. planirostris plani- 

 rostris has spread over the whole continental area from Central 

 Brazil to S. Mexico ; the complete resemblance, even in average 

 size, between specimens from jNTexico and S. America, and the 

 absence of the I'ace from any of the West Indian Islands, are 

 evidence that it has reached Central America (N. of the Nicaragua 

 depression) and INIexico in a very recent epoch, at all events at a 

 time when the Greater Antilles were separated from the mainland 

 bv Avater of suflicient breadth to constitute an absolute barrier for 

 the spreading of the race from the latter into the former. A. p. 

 trinitatis is apparently confined to the Venezuelan coast islands, 

 Trinidad and Tobago, ^1 . jJ- grenadensis to Grenada. These three 

 races are so extremely closely inter-related, being distinguishable 

 only by small average differences in size, that from a broader 

 point of view they may be regarded as one form. In relatively 

 strong contrast to this form stands the large-skulled, large-toothed, 

 and as a rule also externally larger-sized .-1. p. fallax, the true 

 home of which seems to be Guiana, a part of S. America which in 

 a late geological epoch constituted an isolated insular area ; all the 

 Guianan specimens of A. planirostris I have seen (51 in number, 

 collected at different places, by diffei'ent collectors, and at different 

 times) are A. p. fallax ; if, therefore, Guiana is the place of origin 

 of this race, it has spread fi'om there to the Lower Orinoco 

 (Ciudad Bolivar) and Lower Amazons (Para) ; along the numerous 

 sovithern affluents of the Amazons it has probably made its way 

 to Peru (" A. hercules," apparently indistinguishable from A. p. 

 fallax). 



