﻿350 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loo 



no more than groupings of named forms along geographic Unes with 

 each regional assemblage regarded as a "species group." The 

 "species" of the so-called brasiliensis and gabbi groups are no more than 

 lowland races of Sylvilagus brasiliensis, some ranging in Brazil and 

 bordering countries, others in Mexico through Central America, and 

 coastal Colombia and Ecuador, The "defilippi group," consisting of 

 the one and only tapiti described by that name, is the eastern Ecua- 

 dorian form of S. brasiliensis. The "kelloggi group," with kelloggi 

 and chillae, represents tapitis of the forested slopes of the Cordillera 

 Occidental in southern Ecuador. The ^'andinus group" included 

 meridensis of the paramos of the Sierra de Merida, Venezuela, andinus 

 with several subspecies named thereof, of the Ecuadorian highlands, 

 and capsalis of western Peru. All names of these high Andean forms 

 represent scattered populations of geographic races of S. brasiliensis. 

 Former taxonomic separation of the "species groups" followed the 

 convenient pattern of bestowing on the same animal a different 

 specific name for each of its representatives on each of the American 

 continents and on each side and slope of each mountain chain. None 

 of the geographical featmes mentioned have impeded the distribution 

 of S. brasiliensis. The only apparent limiting factors to the hori- 

 zontal and vertical spread of tapitis are absence or extreme scarcity of 

 food, and areas invaded or otherwise occupied by cottontails or, in 

 Argentina, by European leporids and the harelike histricomorph 

 rodents Dolichotis and Pediolagus. 



Of above-mentioned tapitis, only those of the paramos of Ecuador 

 (andinus) and Venezuela (meridensis) are sufficiently differentiated 

 from other forms of S. brasiliensis to merit special discussion. These 

 highland tapitis are remarkably similar in their long, thick fur, dusky 

 color, pale limbs, gray cheeks, and in all cranial characters. Their 

 habitats, situated in the highest altitudinal zone of the Andes capable 

 of sustaining mammalian life, are ecologically similar. Neither 

 andinus nor meridensis could have originated directly from the other. 

 Their respective ranges are completely isolated by the length and 

 ecological diversity of the Colombian portion of the Andean system. 

 It is imperative, therefore, to regard andinus and meridensis as col- 

 lateral offshoots from a common stock of tapitis with an unbroken 

 distribution at lower altitudinal levels. This is, in effect, demon- 

 strably true. S. b. andinus grades into the more warmly colored 

 kelloggi of the Temperate Zone scrub forests of the Ecuadorian Andes. 

 The latter is almost indistinguishable from chillae of the subtropical 

 forests of Ecuador. S. b. chillae, in turn, grades into daulensis of the 

 coastal plain of Ecuador. The lowland or coastal tapitis, whether 

 called daulensis, brasiliensis, or gabbi are the common stock whence 

 diverged localized forms. Tapitis of the Colombian Andes, apolli- 

 naris, nicefori, fulvescens, and salentus, exhibit characters that, on the 



