V 



the natural Distribution of Insects and Fungi. 51 



The theoretical difference between affinity and analogy may 

 be thus explained* : Suppose the existence of two parallel series 

 of animals, the corresponding points of which agree in some one 

 or two remarkable particulars of structure. Suppose also, that 

 the general conformation of the animals in each series passes so 

 gradually from one species to the other, as to render any inter- 

 ruption of this transition almost imperceptible. We shall thus 

 have two very different relations, which must have required an 

 infinite degree of design before they could have been made 

 exactly to harmonize with each other. When, therefore, two 

 such parallel series can be shown in nature to have each their 

 general change of form gradual, or, in other words, their rela- 

 tions of affinity uninterrupted by any thing known ; when more- 

 over the corresponding points in these two series agree in some 

 one or two remarkable circumstances, there is every probabi- 

 lity of our arrangement being correct. It is quite inconceivable 

 that the utmost human ingenuity could make these two kinds of 

 relation to tally with each other, had they not been so designed 

 at the creation. A relation of analogy consists in a correspon- 

 dence between certain parts of the organization of two animals 

 which differ in their general structure. In short, the test of such 

 a relation is barely an evident similarity in some remarkable 

 points of formation, which at first sight give a character to the 

 animals and distinguish them from others connected with them by 

 affinity ; whereas, the test of a relation of affinity is its forming part 

 of a transition continued from one structure to another by nearly 

 equal intervals. As a relation of analogy must always depend 



first saw Agardh's paper and the work of M. Fries on Fungi. If M. Fries borrowed 

 from his niabter Agardh the idea of distinguishing afiinity and analogy, which is not 

 improbable, Vv^e must at least allow him the merit of having greatly improved this part 

 of the theory. 

 * See Hora Entomologicee, p. 362 et seg. 



H 2 on 



