iiiSTom or THK dystkk. 17 



CHAPTER IV. 

 EEPEODUCTION AND GEOWTH. 



The opinions of authors as to the mode of reproduc- 

 tion in the Oyster may be divided into three : the first 

 and oldest is that of Ulysses Aldrovand, who, under 

 the head Generation, wrote as follows : — " Ostreorum 

 ortus causa putredo quaedam esse videtur," With 

 this quotation I think we may at once dismiss the 

 theory of putridity, from which our old author sup- 

 poses the oyster to be born, merely mentioning that 

 several others of the old writers were of the same 

 opinion. 



That mollusca are produced from ova appears to 

 have been the discovery of an anonymous writer in 

 the Philosophical Magazine, 1603, who states that he 

 saw the young snails issue from their eggs, and that 

 he was afraid to give publicity to his discovery with- 

 out the testimony of other witnesses. This position, 

 however, namely that mollusca are produced from 

 eggs, is not likely to be disputed in the present day. 

 The form which the young assume before (juitting the 

 ovary is a question to which I shall have to refer 

 again ; upon this state depends whether the animal is 



c 



