I. 



ANATOMY OF AMPHIOXUS. 



HISTORICAL. 



The historical progress of our knowledge of Amphioxus 

 has often been told, but for the sake of completeness it 

 may be well to sketch its main outlines once more. 



It is interesting as being one of the few animals that 

 were not known to Aristotle, having been described and 

 figured for the first time in 1778 by the German zoologist 

 Peter Simon Pallas. Pallas based his description on 

 a specimen preserved in spirit, which had been sent to 

 him from the coast of Cornwall; and as he confined him- 

 self to the examination of the external form, he made 

 what may appear to us the somewhat gross error of re- 

 garding it as a Mollusc, a species of slug, and he accord- 

 ingly named it Liniax lanceolatiis. He gives a perfectly 

 recognisable figure of it, but was led astray by its flattened 

 and pleated ventral surface, which might be construed 

 into bearing a faint resemblance to a Molluscan "foot." 



This not very extensive knowledge of Amphioxus served 

 the zoological world for nearly sixty years, until, in 1834, 

 it was discovered for the second time in the Mediterra- 

 nean, by the Italian naturalist, Gabriel Costa. Costa 

 found it on the shores of Posilippo, in the Gulf of Naples, 

 and was the first to make observations on the living ani- 

 mal and to recognise its true nature. He thought at first 



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