114 NATURAL HISTORY OF KERGUELEN ISLAND. 



Tbrougbout the skeleton, miuuteandcareful comparison, boue by bone, 

 shows only close similarity between Chionis and the gnlls, as great as 

 that already signalized in treating of the skuil In short, had we 

 only the skeleton of Chionis to go upon, we should be obliged to place the 

 genus in Laridai ; its peculiarities being less widely diverse from those 

 characterizing that family than are to be found within the limits of the 

 family itself. 



We thus find in Chionis a connecting link, closing the narrow gap 

 between the plovers and gulls of the present day. In our opinion, this 

 group represents the survivors of an ancestral type from which both 

 gulls and plovers have descended. And this opinion is strongly sup- 

 ported by the geographical isolation of its habitat, affording but few 

 conditions favorable to variation.* 



In the practical matter of classification, it is evident that Chionis is 

 not exactly referable to either of the two groups between which it stands. 

 A consideration of its external characteristics, its digestive system, or 

 its osteology, solely, would lead to very widely diverse conclusions. 

 For we have presented in this bird a genus with the general appear- 

 ance, gait, and flight of a pigeon, with the beak and voice of a crow ; 

 with the habits of a wader, yet dreading the water, and with the 

 pugnacity and familiarity with man of a rasorial bird. With the last 

 group its digestive system would certainly place it, to say nothing of 

 the long after-shafts of the feathers. And osteological comparison estab- 

 lishes its position definitely between the gulls and plovers, but rather 

 nearer to the former. 



* It is iuteresting to note iu this couuectiou that the faiiua of Kergneleu Island ia 

 rather remarkable as containing several forms of animal life whose structure would 

 give no clue whatever to their habits, so aberrant has been the progress of their va- 

 riation in the peculiar conditions under which they live. Thus the great southern 

 skua {Buphagus skua antarcticus, Bull. No. 2 Nat. Mus., p. 11) has there adopted the 

 habits of a land-hawk ; three very remarkable genera of apterous Diptera occupy the 

 place and live the life of leaf-eating and carnivorous beetles ; and the only beetles 

 found by Dr. Kidder were curculios (in a country without trees or shrubs), and a small 

 water-beetle {Octhebius), living at a distance from any body of fresh water. The cur- 

 culios lived upon the rocks and moss, and had lost their northern habit of simulating 

 death, while one genus of apterous Diptera had taken pp the habit, and lived upon 

 the leaves of the largest plants there represented. Several orders of insects, includ- 

 ing Hymenopiera, Hemiptera, Orthoptera, and Nmroptera, among the commouest else- 

 where, are here entirely absent ; so that those which are represented are placed among 

 altogether anomalous surroundings. As Latreille has said (Hist. Nat., vol. xi, p. 51), 

 •' La nature en general a un certain nomhre de modeles qu'elle reproduit avec des modificationa 

 dans tons la classes, et meme dans les ordres," 



