314 



SCIENCE. 



[N. S. Vol. III. No. 61. 



As Dr. Kidder states : " The general as- 

 pect of the island is desolate in the ex- 

 treme. Snow covers all the higher hills. 

 Only along the seashore is a narrow belt of 

 herbage, of which the singular Kerguelen 

 cabbage is at once the largest and most con- 

 spicuous component. The weather is also 

 extremely inclement, there being scarcely a 

 day without snow or rain. Violent gales 

 of wind prevail to an extent unknown in 

 the same northern latitude. It was often 

 impossible to go on foot any considerable dis- 

 tance from the home station on account of 

 the severity of the wind. Sir J. Clarke Eoss 

 tells of one of his men being actually blown 

 into the sea, and of saving himself from a like 

 accident only by lying flat on the ground." 

 There are no shrubs or trees on the island. 

 The winter season is remarkably mild. 



This set of climatic conditions, the con- 

 tinued strong winds, the low temperature 

 throughout the j^ear, and the absence of the 

 sun for the greater part of the year consti- 

 tute an environment sufficient, we should 

 think, to account for the disuse and result- 

 ing atrophy of the wings without invoking 

 the aid of natural selection, unless we allow 

 that the principle may work as a final and 

 subordinate factor. At all events, these 

 agencies and disuse should be the first to 

 suggest themselves, as they are so tangible 

 and easily understood. 



Under these conditions the beetles, flies 

 and moths would be driven to seek shelter 

 under stones or by burrowing deep in the 

 damp wet moss. By simple disuse, the 

 wings would begin to atrophy, and after a 

 comparatively few generations become re- 

 duced, or in extreme cases almost entirely 

 lost. Certainly the initial cause is the cli- 

 matic conditions. To these persisting cen- 

 tury after century the organism would di- 

 rectly respond, and we do not see the need 

 of evoking the aid of natural selection, in- 

 genious and speculative as it is, any more 

 than in accounting for the loss of eyesight 



or of eyes, with important parts of the brain, 

 in cave animals, or in deep sea or abyssal 

 forms, we should resort to natural selec- 

 tion. Moreover Darwin himself expressly 

 stated that in the case of cave animals natural 

 selection was not operative. Certainly in the 

 present case disuse due to the direct action 

 of the environment appears to be an effi- 

 cient, adequate cause. 



Vertebrata of the Land ; Fishes, Batrachia and 

 Reptiles. Bj^De. Theo. Gill, Washington. 

 Dr. Gill called attention to the discrep- 

 ancy between the evidence already de- 

 duced from the plants and invertebrates 

 and that which would result from the con- 

 sideration of the higher vertebrates. These 

 discrepancies are in accord with the differ- 

 ences in the geological history of the sev- 

 eral classes. For example, all the families 

 of mammals, so far as certainly known, 

 have originated since the commencement of 

 the tertiary ; most of the prominent families 

 and very many genera of mollusks still ex- 

 isting, flourished at least as early as the 

 Jurassic and Cretaceous. (The Jurassic 

 fresh-water faunas were especially consid- 

 ered.) Fishes are intermediate between 

 those two types. Naturally, the persistence 

 in duration of the several classes is reflected 

 in the distribution in space. Many fam- 

 ilies of mammals are confined to special 

 zoogeographical continents, but extremely 

 few families of articulates or mollusks are 

 so limited. In fact, we can avail ourselves 

 of the data furnished by the different divi- 

 sions for chronometrical purposes ; the mol- 

 lusk answers to an hour hand, the mammal 

 to a minute hand. The fishes yield data 

 for the determination of intermediate 

 points. Remembering these postulates, the 

 evidence given by the distribution of the 

 fresh-water fishes is significant ; less so is 

 that of the amphibians and reptiles because 

 they have superior means of locomotion. 



