﻿MAMMALS OF NORTHERN COLOMBIA — HERSHKOVITZ 333 



The North American species aquaticus and palustris, assigned by 

 Nelson to Tapeti, arc not nearly related to S. brasiliensis. Sylvilagus 

 aquaticus is here regarded as a true cottontail though larger and 

 more highly specialized for an aquatic habitat than any other species 

 of the subgenus Syluilagus. The name Limnolagus, therefore, is 

 transferred from the synonymy of Tapeti into that of typical Sylvilagus, 

 where it remains available. The swamp rabbit, Sylvilagus palustris, 

 is even more highly specialized than S. aquaticus for aquatic and 

 palustrine life. Moreover, as is shown under the next heading, the 

 characters of S. palustris combine a number of pecularities that dis- 

 tinguish this species just as certainly from true cottontails (subgenus 

 Sylvilagus) as from tapitis (subgenus Tapeti) and from all other 

 American rabbits as well. It is proposed, therefore, to establish 

 Bachman's Lepus palustris as type of a new subgenus of Sylvilagus, 

 to be known as Paludilagus. Brachylagus and Uomerolagus are 

 apparently valid genera, while Microlagus is currently contained in 

 the synonymy of typical Sylvilagus. 



COMPARISONS AND RELATIONSHIPS OF SOUTH AMERICAN 



LEPORIDAE 



All named forms of South American cottontails grade into one 

 another and are specifically indistinguishable from North American 

 representatives of Sylvilagus floridanus. Recent discoveries of the 

 Central American S. floridanus hondurensis Goldman (1932, p. 122) 

 and S.f. costaricensis Harris (1933, p. 3) fau'ly fill the distributional 

 gap between North and South American cottontails. The blackish 

 nuchal patch of South American continentis and nigronuchalis is a 

 relatively simple character comparable to the blackish upper side of 

 the tail of some Central American cottontails, notably hondurensis. 

 In all cases complete gradation from the blackish to the rufous con- 

 dition characteristic of most cottontails is demonstrable. 



South American representatives of Sylvilagus floridanus are dis- 

 tinguished from S. cunicularis by smaller bulla, shorter palatal 

 bridge, and less developed and defined anterior angle of supraorbital 

 process. They differ from S. graysoni in the same respects except for 

 a greater resemblance in shape of angle of supraorbital process. 

 South American cottontails diverge widely from other North American 

 relatives such as nuttallii, auduhonii, and bachmani and need no com- 

 parison with them. 



The tapiti, Sylvilagus brasiliensis (including gabbi of Central Amer- 

 ica), is smaller than S. floridanus. The rudimentary tail, indistinguish- 

 able from the similarly colored rump, and six, not eight, teats are 

 other marked external characters of the tapiti. Structure of the 

 skuU of S. brasiliensis is highly variable but generally conforms to 

 that of S. floridanus. No constant difference between brasiliensis and 



