124 AMERICAN JOURNAL 



parison with the higher animals would prove the contrary. The 

 following principles are those which I have found most usefulas 

 a guide in systematic inquiries : 



I. " There is but one system, and that is to be read in nature, 

 and was not devised by man. The essential divisions of that 

 system cannot be arbitrary." Agassiz on Classification, p. xix. 



II. " There will be no scientific evidence of God's working in 

 nature until naturalists have shown that the whole creation is 

 the expression of a thought and not the product of physical 

 agency." Agassiz' Lake Superior, 1850, p. 195. 



Many varieties and subspecies owe no doubt their existence to 

 the influence of exterior physical agents, but all higher divisions 

 may be considered created in concordance with the physical cir- 

 cumstances under which the individuals are destined to live ; at 

 least the contrary is not yet proved. 



III. Each systematic division may be considered an indepen- 

 dent body, whose subordinate divisions or parts may be arranged 

 according to a common consequent plan in each Subkingdom. 



Expl. — If, for instance, the presence of a male organ or lungs 

 is considered a character of superiority among Vertebrata, it 

 must be so in the other Subkingdoms also, until the contrary can 

 be proved. 



IV. The greatest resemblance between two divisions is always 

 found in the lowest species or groups of a series. The highest 

 species or group in a division is that which differs most from the 

 lowest in the preceding division. Thus only the lowest plants 

 have locomotion and copulation (budding) in common with ani- 

 mals. " The highest plant, as a plant, is that which differs most 

 from animals," Buguoi. The struthious birds are not the highest 

 birds, although most resembling the mammalia. 



y. The relation between two divisions may be either direct or 

 collateral*. The first kind may be indicated as superior or in- 

 ferior, the latter kind of relation as macrosthenic and micro- 

 sthenic.f Dana has proposed the following terms in place of 

 superior and inferior, viz : Hypertypic (Homo), Alphatypic (Ca- 

 tarrhina), Betatypic (Platyrhina), Gammatypic (Strepsirhina), 

 Hypotypic (Carnivora) Hemitypic or Degenerative (Pinnigrada.) 



Expl. — Mammalia and Birds are macrosthenic ; Herpethia and 



* Milne Edwards' Sur la Classification Nat. des Animaux. An, des Sc. 

 1844, i. p. 80. 



t These terms are used here in a somewhat different sense from that 

 originally proposed by Dana (American Journal of Science, &c., 1863, 

 vol. 36, p. 1.) 



