THE COASTS OP SICILY. 63 



than the Fish, together with a circulating apparatus 

 and a mode of digestion which remind us of similar 

 organs in the Annelids, &c. 



The attentive study of the Amphioxus has led to 

 consequences of the highest importance both to 

 zoology and physiology. Confirming in this respect 

 the embryological results to which we have already 

 referred, it shows us in this degradation of an animal, 

 a permanent condition which recalls in certain 

 respects the transitory condition of the most perfect 

 animals belonging to the same type. Thus during 

 the first periods of its development, the embryo of 

 an ordinary fish, as for instance a Salmon, possesses 

 peculiarities of organisation which remind us of those 

 which we observe in the Amphioxus, but whilst 

 these peculiarities are persistent throughout the 

 whole life of the latter animal, they are soon effaced 

 in the young salmon to give place to other definite 

 characters. The embryology of the Annelids ex-' 

 hibits precisely similar facts ; thus, for instance, in 

 the early period of its existence, the larva of the 

 Terebella closely resembles a Nemertes, and thus the 

 results which have been furnished by the anatomy 

 and embryology of Fishes and Annelids are perfectly 

 in accordance with one another, notwithstanding the 

 great distance which separates these two groups.* 



By the very fact of its degradation, the Amphi- 

 oxus departs from the Vertebrata to approximate 



* Let us once more remind our readers that we speak here of 

 partial resemblances and not of identity. A young Terebella is at 

 no time an adult Nemertes, nor can a Salmon ever have been an 

 Amphioxus. 



