27 

 VI. THE MAIN FACTS CONCERNING THE LANCELET (AMPHIOXUS 



LANCEOLATUS). 



Few animals are cosmopolitan. Changes of climate, food, and 

 habits, brought about by life in other latitudes, alter, directly or 

 indirectly, sooner or later, some features of the body, and the migrant 

 becomes a new variety, and even in course of time may have this 

 variation so indelibly impressed upon it, as to constitute a new 

 species. Even migrant civilised man, with all his special advantages 

 of constant inter-communication with his original stock, is affected 

 appreciably in comparatively a short time. The American our 

 Brother Jonathan has not our features, but bears a physical trade- 

 mark solely his own ; our cousin, too, in New Zealand a really 

 nearer relative than he from the U. S. A. is developing " points " 

 alien to ours. Naturally however, the land is less likely to present 

 cosmopolitan types than the sea. Under the waves vicissitudes of 

 climate are reduced to a minimum. But even there, we but seldom 

 find a species stable over widely extended areas ; those known to be 

 world- wide may practically be counted on the fingers. 



Thence, when we find that perhaps the most curious of living 

 animals, the strange Lancelet, most lowly among the vertebrates, is 

 found without appreciable change of form or structure in the seas of 

 Europe (around Britain and in the Mediterranean), along the North 

 American coast, in the West Indies, Brazil, Peru, Tasmania, Australia, 

 and Borneo, we seize one of the many noteworthy facts concerning 

 this animal. 



Spread thus universally, Awiphio&us lanceolatus is not only the 

 sole species in its genus, but also the only representative of the 

 family, and even of the group to which it belongs. Curiously enough, 

 the first example known, was caught off Cornwall, and passed into 

 the possession of the early Russian naturalist Pallas, who indeed saw 

 so little affinity with the vertebra ta, that he described it (1774) as a 

 slug, Limax lanceolatus. Some fifty years passed ere we have note 

 of a second specimen being caught (1831). This again was taken on 

 our English coast, at Polperro, Cornwall. It was well described by 

 Yarrell, who bestowed upon it the name we are now so familiar with, 

 Amphioxus lanceolatus. Yarrell recognised its relationship better, 

 and placed it at the bottom of the list of fishes, where it has ever 

 since remained. 



The growth of the systematic study of marine life has of late 

 years shown Amphioxus to be both widely spread and frequently 

 numerous, so that now it may aspire to join the select circle of 

 martyrs to science, already adorned with the names of the frog 

 and the dogfish. 



