THE CIRCUliAR THEORY EXPLAINED. 321 



This, the student may probably say, is a simple series, 

 beginning with birds, and proceeding in a direct line to 

 tortoises ; but if so, the question arises, which is the 

 next class ? what animal is there which belongs to a 

 class different from that of the reptiles, but which makes 

 the nearest approach to a tortoise ? The ornithologist will 

 immediately point to the penguins. These are indeed 

 birds, but they cannot fly ; they have feathers, but they 

 are so formed as to resemble scales ; they have wings, 

 but they are transformed into the shape, and perform 

 the same oflice, as the fore-feet of the turtle ; both lay 

 their eggs, without a nest, upon the sand, and both seem 

 out of their natural element when they are upon the dry 

 ground. There still is, it is true, a great difierence be- 

 tween them ; but that is not the immediate question ; 

 the point we must keep in view is this, what animals are 

 ■we to place after the tortoises .'' They are preceded by 

 the reptiles, but by what class are they followed .'' if the 

 penguins possess a greater similarity to them than any 

 other existing race, then these birds must be placed next 

 in succession, and we consequently come back again to 

 the first class of animals we commenced with, namely, 

 birds ; the series thus forms a circle, and this union 

 is expressed when it is said, " that the circle returns 

 into itself." 



(389.) If any one of our readers find a difficulty in 

 fully comprehending the mode by which a series of 

 animals forms a circle, let him take a straight piece 

 of cane, and affix to it, at equal intervals, the fol- 

 lowing labels : penguins, birds, quadrupeds, fish, frogs, 

 reptiles, tortoises. That with "penguins" will, of course, 

 be the first, and that with "tortoises" the last. Let him 

 then bend the cane into a hoop, the first label and the 

 last will thus be brought together without deranging 

 the rest of the series ; by this contrivance he will ini- 

 mediately comprehend what is meant by a " circle of 

 affinity," " a circular succession," " the closing of a 

 circle," or " a circle returning into itself;" all which 

 phrases are only different modes of expressing that circu- 



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