CXXX1V INTRODUCTION. 



nization, as distinguished from the Hydree ; that is, they 

 were strictly a CLASS *. 



As to the form of the word, it seems to me to be a 

 point of the very smallest moment. No doubt Polyzoa 

 would be the proper reading, if we must of necessity 

 accept Thompson's original error in the construction of 

 the word f. But it is surely allowable to alter the ending, 

 and so bring the term into harmony with our present 

 usage. In doing so we retain all that is essential, and 

 we leave the honour with him to whom it is justly due. 



Bronn's criticism that the term Polyzoa is not dis- 

 tinctive, and may properly be used of other groups besides 

 the present, has a certain weight ; but if we were to em- 

 ploy the principle which it implies as a practical test of 

 our nomenclature, it would involve not the mere displace- 

 ment of a single name, but widespread change and con- 

 fusion. 



Thompson's name, then, seems to me to have every claim 

 to adoption ; and as uniformity in scientific nomenclature 

 is clearly desirable, I shall still venture to hope that conti- 

 nental zoologists may not be unwilling to reconsider the 



* The following passages may be added, as showing clearly the sense in 

 which Thompson used the term Polyzoa : " The other species of Sertnluria 

 in which the animals have been determined to be Polyzoce may, . . . perhaps, 

 be referred to one genus." "The present Memoir has for its object to de- 

 monstrate another form of animal not hitherto known, and which, while it 

 must be allowed to belong to a new type of Mollusca Acephala, resembles 

 exteriorly in some manner the Hydra ; this animal has been designated by 

 the name of Polyzoa." In this passage both Hydra and Polyzoa are used 

 to denote types of stnicture, and not elements of the compound organism. 



In the prospectus of the whole work, we find the following as the subject 

 of the 10th Memoir: "Animals of some Cellarice, Tubuliporce, and Flus- 

 tracea proved to be Polyzoae." To substitute polypides for polyzoa in thii 

 sentence would be to render it perfectly unmeaning. 



t Thompson himself once uses Polyzoa as the plural form. Mem. 5, 

 p. 96. 



