18431882] RANGES OF GENERA 403 



over thousands of miles in their respective countries ; on the Letter 314 

 other hand, no genus of monkey ranges over so large a part 

 of the world, and the individual species in their respective 

 countries seldom range over wide spaces. I suspect (but am 

 not sure) that in the genus Mus (the most mundane genus of 

 all mammifers) the individual species have not wide ranges, 

 which is opposed to my query. 



I fancy, from a paper by Don, that some genera of grasses 

 (i.e. Juncus or Juncaceae) are widely diffused over the world, 

 and certainly many of their species have very wide ranges 

 in short, it seems that my question is whether there is any 

 relation between the ranges of genera and of individual 

 species, without any relation to the size of the genera. It 

 is evident a genus might be widely diffused in two ways: 1st, 

 by many different species, each with restricted ranges ; and 

 2nd, by many or few species with wide ranges. Any light 

 which you could throw on this I should be very much obliged 

 for. Thank you most kindly, also, for your offer in a former 

 letter to consider any other points ; and at some future day 

 I shall be most grateful for a little assistance, but I will not 

 be unmerciful. 



Swainson has remarked (and Westwood contradicted) 

 that typical genera have wide ranges : Waterhouse (without 

 knowing these previous remarkers) made to me the same 

 observation : I feel a laudable doubt and disinclination to 

 believe any statement of Swainson ; but now Waterhouse 

 remarks it, I am curious on the point. There is, however, 

 so much vague in the meaning of " typical forms," and no 

 little ambiguity in the mere assertion of " wide ranges " (for 

 zoologists seldom go into strict and disagreeable arithmetic, 

 like you botanists so wisely do) that I feel very doubtful, 

 though some considerations tempt me to believe in this 

 remark. Here again, if you can throw any light, I shall be 

 much obliged. After your kind remarks I will not apologise 

 for boring you with my vague queries and remarks. 



To J. D. Hooker. Letter 315 



Down, Dec. 25th [1844]. 

 Happy Christmas to you. 



The following letter refers to notes by Sir J. D. Hooker which we 

 have not seen. Though we are therefore unable to make clear many 



