ZOOLOGICAL NOMENCLATURE 247 



In case of larva and adult or male and female, formerly considered 

 different animals but subsequently found to be the same, the oldest 

 available name becomes the name of the species. 



Another point is that names are not definitions, consequently the fact of lack of 

 appropriateness of any name is no objection to its continuation. This will appeal 

 to anyone as a wise provision, because if a different name were substituted each time 

 a designation more descriptive or applicable was invented it would be utterly destruc- 

 tive to system. When it is considered that some of our parasites have approximately 

 fifty different designations, for the most part given by medical observers, it will be 

 appreciated how much the zoologist has aided us in trying to eliminate all but the 

 single proper zoological name. 



It is a rule of zoological nomenclature that zoological names are 

 independent of botanical ones so that the prior use of a generic name 

 for a plant is not an objection to its use for an animal. 



The objections so frequently heard among physicians in connection with adopting 

 new names for old ones are not well founded. Wherever confusion has reigned, the 

 establishment of order always results in temporary greater confusion. There 

 is no doubt that the student taking up this subject a few years hence will have the 

 satisfaction, thanks to the zoologist, of only having to burden his mind with one name 

 for one parasite. 



There is only one correct 'name for an animal and all other names 

 are synonyms. 



The principal cause of changes of names is that our conception of the relationships 

 of animals changes. 



5. Terminology. This applies to appropriate designations for different organs, 

 symptoms, etc., and is not subject to any rule other than that of good usage. 



Thus the terms cirrus in the case of the male copulatory organ of flukes, spicule 

 for the same in nematodes and penis in connection with insects would be instances 

 of terminology. 



6. Pseudoparasitism. Where organisms enter the body accidentally and when 

 such sojourn in the body of man plays no part in the life history of the organism 

 we employ the term pseudoparasitism. For example: Fly larvae swallowed by 

 man and passed out in the faeces. We also use the terms temporary parasites 

 (bedbug) and permanent parasites (liver fluke). 



7. Hosts. The animal in which a parasite undergoes its sexual life is called the 

 definitive or final host, that in which it passes its larval existence the intermediary 

 host. For example: Man is the intermediary host of the malarial parasite, the 

 mosquito the definitive host. A single animal may, however, be both definitive 

 and intermediary host; thus Trichinella may pass its larval existence in the muscles 

 of man and its sexual life in his intestines. 



8. Heredity, Congenitalism. Hereditary characteristics are those which were 

 present in the ovum or spermatozoon before fertilization; congenital ones those 

 which occur after fertilization. South African tick fever is probably an instance 



