MONSTROSITIES 



277 



Mr. Hutchinson evidently did not feel satisfied that the usual 

 small variations have been always sufficient to account for certain 

 structural phenomena which would seem to leave unexplained 

 gaps behind them in the course of development For after stating 

 that surroundings must have had a great deal to do with the 

 changes wrought on the structure of animals, he says : x ' There is, 

 however, another cause which may be of even greater importance, 

 although it cannot be so easily understood and that is internal 

 changes in the animal itself. All the creatures we see around us 

 are constantly varying, and have done so in the past now in one 

 direction, now in another. The cause of " variation " is one of the 

 unsolved problems of modern biology or the study of life ; but we 

 do know that a variation occasionally happens to be of such a 

 kind as to make a radical change in the organism, and to fit it 

 for new conditions of life better than its comrades of the same 

 species.' As an example of such a change he quotes the power of 

 * gestation,' ' whether acquired at once, by some individual, or only 

 slowly brought about after many generations.' 



Zoologists have invented the terms * aberrant forms ' to denote 

 forms of animals which do not conform to the theory of ' gradual 

 accumulation of small variations.' 



Among fishes there are numerous forms which might have 

 originated in a sudden * aberration.' For instance, there are two 

 forms of Sword-fish, the ordinary one (Hi$topheru$\ with its 

 itpper jaw prolonged into a sword-like point ; and various species 

 of Hemiramphiits? These have the lower jaw prolonged in a sword- 

 like point. Both these forms may have originated suddenly in 

 fishes with equal jaws, either by a monstrous enlargement of one 

 jaw, if both jaws were small, or by a monstrous dwarfing of one 



1 Creatures of Other Days, p. 178. 



2 Fishes of India , by Francis Day, part iii. pi. cxix. 



