The Zoologist — January, 18G9. 1527 



catalogue llie presumption would rather be against tbe first species ; for suppose three 

 genera, A, B and C ; the arrangement being necessarily linear, and following tbe 

 affinities of the species, the first species of genus B would be that which most nearly 

 approached genus A, just as the last species of genus B would be that which most 

 nearly approached genus C ; and it would be neither at the top, nor at the bottom, but 

 about the middle, of genus B, that we should find the species of B which was most 

 different from both A and C, which species would presumably be the ideal representa- 

 tive of genus B, would presumably have that aggregate of characters which constitute 

 the genus B, and distinguish it from A on the one hand and from C on the other. 



I hold therefore, not only that Mr. Kirby's rule is inappropriate to the past, but 

 that it would be an unhappy rule to adopt for the future. 



I conceive thai the practice hitherto has been a tacit recognition of the proposition 

 enunciated by Mr. Stainton — that when a genus (of which no type Las been indicated) 

 comes to require division, the author who performs that operation is the person with 

 whom it lies to decide which of the dissevered parts shall retain the original name. 

 This practice has worked pretty well in the past, and will suffice for the future. 

 I apprehend that the evils which have arisen in tbe past have been caused by the fact 

 that the separatist, failing to recognise the original atilhor's indications of typicality, 

 has applied the rule to cases which were not properly within its range. But assuming 

 that the separatist has not disregarded the original author's indications, or in other 

 words that the case was a proper one for the application of the above rule, then 1 hold 

 that his determination ought to be final and conclusive on writers subsequent to him, 

 and is entitled to the full benefit of the law of priority. 



But whilst agreeing to the above proposition, Mr. Janson goes a step further; 

 whilst leaving the second author at liberty, he frees him from any obligation, to 

 retain for either division the name given by the first author. And I believe 

 some naturalists go a step further still, and say that the second author ought 

 not to retain the original name as the name of either division, but should give 

 a new name to each division. That is to say, because we cannot call by the 

 name of Papilio all the species which Linne included under that name, therefore we 

 shall not call any of the species by that name. It is quite true that the Papilio of 

 Latreille is not co-extensive with the Papilio of Linne; the Papilio of this century is 

 only part of Papilio of the last century ; to the characters, as given by Linne, admitting 

 a very wide range of forms, Latreille has superadded other characters, possessed by 

 some but not by all those within the Linnean range ; the effect is to restrict the 

 application of the name to a part only of the insects which Linne recognised under the 

 term Papilio; but every species of the Papilio of Latreille must be a species of the 

 Papilio of Linne, not necessarily known to Linne, but within the description given by 

 him. Florence remains an Italian city notwithstanding that Mentone has been taken 

 from Italy. Machaon may remain a Papilio notwithstanding that Priamus has been 

 removed. There is no misapplication of the name Papilio — only a narrowing of its 

 application. 



Consider the consequence of the rejection of the older name, instead of the 

 restriction of its limits. Genus A is divided into two; each receives a new name, 

 B and C : there is no longer a genus A. A few years later B and C are subdivided, 

 B into D and E, C into F and G : there is no longer a genus B or a genus C. A few 

 years later tbe same process is applied to D, E, F and G : these iu turn are discarded, 



