the Natural Distiibulion of I/isects and Fu)i"i. lo'j 



feriint, sed citeriora congruunt, qu£e in habilii externo et cha- 

 racteribus accidentalibus mutandis maxime valent. Ubicumque 

 ill Historia naturali oculos convertinius, singulum organismum 

 multiplicia hujus oft'erunt exemplu. Systenia mycologicuni 

 intra explicatuni his omnino nititui". Clavaria et Peziza, Bia- 

 tora et Bceoinijccs affines. sunt ; sed Clavaria et Ba:omijccs, Pe- 

 ziza et Biatora analogre, c. s. p. in infinitum. 



" Comparatio Linnasana afiinitatis plantarum cum ma]:)])a 

 geographicfi baud ignobilis visa iliit; ignoscatur igitur mihi 

 banc ita extendenti, ut affinitas in bac indicet longitudlncm et 

 analogia latitudinem. 



" Neque boo tantum in inferiores classes quadrat. Naturae 

 leges ubique barmonicse. Si systema mycologicum et prin- 

 cipia quibus nititur, omnibus non dispbcerent, totius regni 

 vegetabilis dispositionem demonstrare conaboi". Plurimajam 

 elaboravi." 



Relations of affinity being tbus separated from those of ana- 

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

 tion of wliat M. Agardb tei-ms tlie affinity of Transitus^ namely, 

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

 no groups of sj:)ecies (whatever may be the rank of these groups) 

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

 nities returning into themselves, and forming as it were circles 

 which touch other circles. Such only are natural groups. 

 This was said of insects*; and our author, looking only at 

 })lants, and principally at Fungi, comes to the same conclu- 

 sion, as appears from the following words : " Species unica in 

 natura fixe circumscripta idea. Superiores nullas agnovimus 

 sectiones strictissime circumscriptas, tantum circulos plus 

 minus clauses, affines vero ubique tangentes. Hos tribus, 

 genera, sectiones, &c. simulque si naturae vestigia sequuntur, 

 naturales dicimus." 



That the circle, indeed, is not always closed or complete has 

 been observed likewise in the animal kingdom; and there are 

 two ways of accounting for it. First, that tlie beings which 

 would render tlie circle complete have not yet been discovered ; 

 a conclusion to which we readily arrive on considering- Iiow 

 little is yet known of natural productions ; and secondly, that 

 there are hiatus or chasms which do really exist in nature, 

 and which may be attributed to the extinction of species in 

 conse(|uence of revolutions undergone by the surface of tiiis 

 globe. Whether one only or both of these reasons be recjui- 

 site to account for circles of affinity not always a]i]iearin'>- com-r 

 plcle, wc shall not at present investigate ; contenting ourselves 



* lllirO' KllldDlolnn/ciC, p. ]')!), <lvc'. 



with 



