CHECKLIST OF THE SNAKES OF MEXICO 5 



blage of subspecies of a single species, or to all the subspecies of a 

 single species, or to a group of species (and their races) of a single 

 genus, or to all the species of a single genus. Assemblages of related 

 genera we prefer to call "sections." The essential value of the term, 

 "group" is in the implication of relationship. 



The application of the "homonym rule" of the International Code 

 of Zoological Nomenclature to the taxonomy of forms included in this 

 checklist has met with some difficulty, owing to the loose statement of 

 the rule and the varied interpretation of it by various taxonomists. 

 The difference of opinion concerns the application of the rule to 

 secondary and primary homonyms. At this point it may be well to 

 define primary homonyms as scientific names which, as first proposed, 

 are identical both in generic and specific name with another, also in 

 its original form. Secondary homonyms are scientific names that, in 

 their form as originally proposed, are not the same as any other name 

 in its original form; they become homonyms only by transference of 

 the name to another genus, or by transference of another, identical 

 specific name of another genus to that which contains the new name. 

 Primary homonyms are created only when both generic and specific 

 (or subspecific) names are identical in the original combinations of 

 two or more scientific names. For example, Conophis lineatvs 

 similis Smith and Conophis pulcher similis Bocourt are primary 

 homonyms. But Stenorhiiia quinqwelineata Jan (a new name) is a 

 secondary homonym of StenorhiTia quinquelineata (Hallowell), since 

 the latter is not in its original form, having been transferred from 

 its original genus {Microphis) . There are several grades of second- 

 ary homonyms, but among them are not included strictly implied 

 homonyms (tertiary homonyms), which have no significance in the 

 present problem. Tertiary homonyms are created upon combination 

 of genera or species, without citation of the species or synonyms in- 

 volved by the combination ; these homonyms are clearly implied, and 

 while they have some standing in other taxonomic problems, here 

 they fortunately have none. 



In the past we have interpreted the "homonym rule" to require 

 permanent suppression of secondary as well as primary homonyms, 

 but this view has been abandoned in favor of its alternative, that only 

 primary homonyms aire permanently suppressed. Our decision is 

 based upon the realization that several undesirable results would fol- 

 low official recognition of suppression of secondary homonyms; we 

 are convinced, moreover, that the intention of the rules, as stated, was 

 application only to primary homonyms. As an example of one unde- 

 sirable result, careful examination would be required, not so much 

 of the best and most authoritative works, but rather of the poorest 

 and least known portion of the literature (including educational and 



