326 Mr, Macleay on certain general Laws regulating [Noy. 



tions of Affinity ; for, as our author M. Fries truly says, *^ Quo 

 magis in siiperjicie acquieverunt natures scrutatores, eo magis 

 analoga cum affinibus commutdruntJ 



The ideas of affinity and analogy are so distinct from each 

 other in the mind of every person acquainted with the first 

 principles of logic, that even while this distinction was not laid 

 down as an axiom in natural history, experienced naturalists 

 perceived that every correspondence of character did not neces- 

 sarily constitute an affinity. Thus the celebrated Pallas, in his 

 Elenchus Zoophytorum, has well observed that Bonnet, in order 

 to complete his hnear scale of nature, was obliged to abandon 

 the true vinculum of affinity, and to resort to such superficial or 

 analogous characters as those which connect Vespertilio and 

 Exoc(£lus with birds. But the nature of the diffi^rence which 

 exists in natural history between affinity and analogy, was I 

 beheve first discovered in studying Lamellicorn Insects ; and in 

 the year 1819, when I published that discovery, the fifth part 

 of an acute philosophical work, entitled Botanical Aphorisms,''^ 

 appeared in Sweden, wherein the distinguished cryptogamist 

 M. Agardh proves by the following words, that he likewise had 

 a slight glimpse of the same truth : *^ Analogia qusedam et simi- 

 litudo in diversis seriebus vegetabihum interdum cernatur, quasi 

 progressa esset natura ad perfectionem per eosdem gradus sed 

 diversi via.f" 



The next work in which the distinction appeared was the 

 Memoires du Museum d'Histoire Naturelle ; in a part of which, 

 published in the autumn of 1821, a paper was inserted by 

 M. DecandoUe on the natural family of Cruciferee, Here this 

 botanist states, that he finds it possible to express in a table all 

 the affinities existing in this family of plants by what he terms a 

 double entrte ; in other words, he supposes that there are trans- 

 versal affinities as well as direct ones, — a notion of the reality 

 however which appears to be much more confused than that 

 previously entertamed by M. Agardh, and explained as above in 

 his Botanical Aphorisms. 



» Aphorismi Botanici, quos venia Ampliss. Ord. Philos. Lund. Praeside Carolo Ad. 

 Agardh, &c. pro Gradu Philosophico, p. p. N. Kuhlgren, &c. p. v, Lundae, 1819. 



+ In the same little tract M. Agardh makes two other observations, which coincide 

 witli what I have noticed ia tlie Animal kingdom. The first is as follows : " Inter in- 

 feriores formas superiores saipe efflorescunt, sed rudes et veluti experimenta : sic antici- 

 pationes formae perfections in plantis inferioribug non raro obveniant; ut etiam in 

 plantis superioribus regressus ad formam imperfectiorem." Now in the IJoree Ento- 

 mologiccE^ p. 223, I have attempted to show that Nature, in the imperfectly constructed 

 jicrila^ sketches out in a manner the five principal forms of the animal kingdom. So 

 also the direct return of Annulose Vermes to Acrita is repeatedly asserted in the same 

 work : this however seems to depend more properly on M. Agardh's other observation, 

 viz. '' Duplex est itaque affinitas plantarum, aut ea, quae oritur e transitu ab una forma 

 normali ad alteram, aut ea, quae versatur imprimis in anticipatione formee superioris aut 

 regressu in formam inferiorem. Illam affinitatem trunsHus appeilamus, banc transuUa- 

 tionis.** This affinity of transultalion is evidently nothing else than the disposition ob- 

 servable in opposite points of the same series or transitus of affinity to meet each other, 

 and of which I have given various examples in the JJora Entomologicce, p. 319. 



