358 ORIGIN OF SPECIES 



forms are now commonly admitted to be teleostean ; and even 

 some palaeozoic forms have thus been classed by one high 

 authority. If the teleosteans had really appeared suddenly in 

 the northern hemisphere at the commencement of the chalk 

 formation, the fact would have been highly remarkable; but 

 it would not have formed an insuperable difficulty, vmless it 

 could likewise have been shown that at the same period the 

 species were suddenly and simultaneously developed in other 

 quarters of the world. It is almost superfluous to remark 

 that hardly any fossil-fish are known from south of the 

 equator ; and by running through Pictet's Palaeontology it will 

 be seen that very few species are known from several forma- 

 tions in Europe. Some few families of fish now have a con- 

 fined range; the teleostean fishes might formerly have had a 

 similarly confined range, and after having been largely de- 

 veloped in some one sea, have spread widely. Nor have we 

 any right to suppose that the seas of the world have always 

 been so freely open from south to north as they are at pres- 

 ent. Even at this day, if the Malay Archipelago were con- 

 verted into land, the tropical parts of the Indian Ocean would 

 form a large and perfectly enclosed basin, in which any great 

 group of marine animals might be multiplied; and here they 

 would remain confined, until some of the species became 

 adapted to a cooler climate, and were enabled to double the 

 Southern capes of Africa or Australia, and thus reach other 

 and distant seas. 



From these considerations, from our ignorance of the geol- 

 ogy of other countries beyond the confines of Europe and the 

 United States, and from the revolution in our palaeontological 

 knowledge effected by the discoveries of the last dozen years, 

 it seems to me to be about as rash to dogmatize on the suc- 

 cession of organic forms throughout the world, as it would 

 be for a naturalist to land for five minutes on a barren point 

 in Australia, and then to discuss the number and range of its 

 productions. 



