794 



THE AMERICAN NATURALIST [Vol. XL 



8(>ine iiHMnl.ors of the nntolope family are well known to l.e pro- 

 tected from inM>(t> l.> l.inU M^e Miiiai.V llnafh ni fin ]'J<lL and 

 other woik. . \ii_Nonr u iio ha. uatdied the .iillVrin^. of cattle 



factor in expelling animals from a certain countrv to which they 

 are naturally adapted by their tooth and foot stnictiire. 



Ticks'. — Ticks, even when nwn-iufection-bearing, form absolute 

 and effective barriers to the introduction of quadrupeds hito certain 

 regions. In certain forested portions of South and Central America 

 they endano-er Innnan life. In certain regions of Africa ticks are 

 practically fatal to horses; as ol)st>rved by Dr. 1). G. Elliot thou- 

 sands of ticks would sometimes gather on a horse as a result of a 

 single night's grazing. The mane especially serves to collect these 

 pests. Thus the falling mane of the northern horse is distinctly 

 disadvantageous as com])ared with the upright manes of the asses 

 and zebras. Ticks are capa!)le of <h i\ ing certain types of animals 

 entirely out of a country and of indirectly causing certain modifi- 

 cations of the hair and epi(hMniis. 



Frontal Air Sinns^^ L.nx.r inx.idinu the frontal sinus of the 

 skull are not to l>c left out of accouni anionu' the possible causes 

 of elimination. An old trajtpcr and ciose obs(M-ver in British 

 Cohnnbia, Mr. Charlrs Smith, informs me (hat both the wild 



^/^/^^/.s are .rriou.b alfe. fd and m ..n.-t inx-- kiih.l Ia im'h.niination 

 caused by these larv:e. The ..vcr-crow.led caribou of Labrador 

 and Newfoundland siilTer from a lly which lays its eggs in the 

 nostril passages. 



In certain of the Koccne Titanothcrcs, in 1 )olich()rhinus espe- 



