I $35.] DISTRIBUTION OV THE ORGANIC BEINGS. 396 



belonged to one species (Mimus trifasciatus) ; all from Albemarle 

 Island to M. parvulus ; and all from James and Chatham Islands 

 (between which two other islands are situated, as connecting 

 links) belonged to M. melanotis. These two latter species are 

 closely allied, and would by some ornithologists be considered as 

 only well-marked races or varieties ; but the Mimus trifasciatus 

 is very distinct. Unfortunately most of the specimens of the 

 finch tribe were mingled together; but I have strong reasons to 

 suspect that some of the species of the sub-group Geospiza are 

 confined to separate islands. If the different islands have their 

 representatives of Geospiza, it may help to explain the singularly 

 large number of the species of this sub-group in this one small 

 archipelago, and as a probable consequence of their numbers, 

 the perfectly graduated series in the size of their beaks. Two 

 species of the sub-group Cactornis, and two of Camarhynchus, 

 were procured in the archipelago ; and of the numerous speci- 

 mens of these two sub-groups shot by four collectors at James 

 Island, all were found to belong to one species of each ; whereas 

 the numerous specimens shot either on Chatham or Charles 

 Island (for the two sets were mingled together) all belonged to 

 the two other species : hence we may feel almost sure that these 

 islands possess their representative species of these two sub-groups. 

 In land-shells this law of distribution does not appear to hold 

 good. In my very small collection of insects, Mr. Waterhouse 

 remarks, that of those which were ticketed with their locality, 

 not one was common to any two of the islands. 



If we now turn to the Flora, we shall find the aboriginal 

 plants of the different islands wonderfully different. I give all 

 the following results on the high authority of my friend Dr. 

 J. Hooker. I may premise that I indiscriminately collected 

 everything in flower on the different islands, and fortunately 

 kept my collections separate. Too much confidence, however, 

 must not be placed in the proportional results, as the small col- 

 lections brought home by some other naturalists, though in some 

 respects confirming the results, plainly show that much remains 

 to be done in the botany of this group : the Leguminosae, more- 

 over, have as yet been only approximately worked out : — 



