328 Mr. Macleay on certain general Laws regulating [Nov. 



same way, and, making allowance for the difference of the ob- 

 jects he was investigating, almost in the same words : " Natura 

 tamen, ubique varia, semper tamen eadem, hoc est, eandem 

 ideam exponere tendit, mutatis modo, qux ex ulteriori ratione 

 necessario pendent ; eadem sequitur principia, ita modo ut infe- 

 riora (v. g. exterior forma, quae in infimis adhuc vaga) superiori- 

 bus cedant. Errant igitur qui distinctiones summas e forma 

 exteriori tantum ducunt ; quis ex hac regnum animale et vegeta- 

 bile definire potuit? Evidentissime hoc demonstrant Lichenes 

 et Fungi. Recentiores horum differentiam in characteribus ex- 

 ternis tantum ponentes cum Fungis jungere voluerunt Le/)raWfl5, 

 Opegraphas, Caliciaj VerrucariaSj d^c. quod nuUo modo probare 

 possum. Altius illorum differentia deducenda. Sed cum na- 

 tura eadem via inter Lichenes et Fungos ubique progreditur, 

 singulum genus Lichenum Fungis correspondet. At haec inde 

 affinia non dicimus ; sed ariahga. 



" Affinia igitur sunt quae in eadem serie sequuntur et in se in- 

 vicem transire videntur. Haec in ullerioribus congruunt sed in 

 citerioribus rationibus differunt. Analoga autem dicimus quae 

 in diversis seriebus locis parallelis* posita sunt et sibi invicem 

 correspondent. Ultima cosmica momenta difierunt, sed cite- 

 riora congruunt, quae in habitu externo et characteribus acci- 

 dentalibus mutandis maxime valent. Ubicumque in Historia 

 naturali oculos convertimus, singulum organismum multiplicia 

 hujus offerunt exempla. Systema mycologicum infra explica- 

 tum his omnino nititur. Clavaria et Peziza, Biatora et B^o- 

 myces affines sunt ; sed Clavaria et Baornyces, Peziza et Biatora 

 analogae, e, s. p, in infinitum. 



" Comparatio Linnaeana affinitatis plantarum cum mappa geo- 

 graphicS. baud ignobihs visa fuit ; ignoscatur igitur mihi banc 

 ita extendenti, ut affinitas in hac indicet longitudinem et analo- 

 gia latitudinem. 



" Neque hoc tantum in inferiores classes quadrat. Naturae 

 legis ubique harmonicae. Si systema mycologicum et principia, 

 quibus nititur, omnibus non dispHcerent, totius regni vegetabilis 

 dispositionem demonstrare conabor. Plurima jam elaboravi." 



Relations of affinity being thus separated from those of ana- 

 logy, we immediately get the following facts from the observa- 

 tion of what M. Agardh terms the affinity of TrausituSy namely, 

 that species form the only absolute division in nature, and that 

 no group of species (whatever may be the rank of these groups) 

 ought to be considered as insulated, but only as series of affini- 

 ties returning into themselves, and forming as it were circles 



♦ As there is some danger of being led astray by our imi^ination when we first at- 

 tempt to separate relations of analogy from those of affinity, it is fortunate that the na- 

 turalist cannot have a more admirable test of his accuracy, or a stronger rein on his 

 fancy, than this parallelism of analogous groups in contiguous series of affinity. Thus, 

 although a solitary resemblance may mislead, it is clear that when we find several of 

 «uch resemblances to keep parallel to each other in contiguous series, we may reckon 

 upon their having some more solid foundation tlian our own fancy. 



