52 Mr. W. S. Macrzay on certain general Laws regulating 
on some marked property or peculiarity of structure, and as that 
of affinity, which connects two groups, becomes weaker and less 
visible as these groups are more general, it is not in the least 
surprising, that what is only an analogical correspondence in one 
or two important particulars, should often have been mistaken 
for a general affinity. | 
M. Fries draws the distinction between them precisely i in the 
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, quæ ex ulteriori ratione 
necessario pendent; eadem sequitur principia, ita modo ut infe- 
riora (v. g. exterior forma, quz in infimis adhuc vaga) superiori- 
bus cedant. Errant igitur qui distinctiones summas e forma 
exteriori tantum ducuit ; quis ex hac regnum animale et vege- 
tabile definire potuit? Evidentissimé hoc demonstrant Lichenes 
et Fungi. Recentiores horum differentiam in characteribus ex- 
ternis tantum ponentes cum Fungis jungere voluerunt Leprarias, 
Opegraphas, Calicia, Verrucarias, &c. quod nullo modo probare 
possum. Altius illorum differentia deducenda. Sed cum na- 
tura eâdem via inter Lichenes et Fungos ubique progreditur, 
singulum genus Lichenum Fungis correspondet. At hæc inde 
affinia non dicimus ; sed analoga. 
** Affinia igitur sunt que in eadem serie sequuntur et in se in- 
vicem transire videntur. Hæc in ulterioribus congruunt sed in 
citerioribus rationibus differunt. Analoga autem dicimus que 
in diversis seriebus locis parallelis* posita sunt et sibi invicem 
. corre- 
- 
» As there is some danger of being led astray by our imagination when we first at- 
tempt to separate relations ef 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 
