Chap. III. niYSIOnilLOSOPIIICAL SYSTEMS. 217 



those of every other groiip, besides forming a circle in themselves; and in order 

 to cany out this idea, all animals are arranged in circular groups, in such a manner 

 as to bring out these analogies, whilst the most obvious affinities are set aside to 

 favor a preconceived view. But that I may not appear to underrate the merits 

 of this system, I will present it in the very words of its most zealous admirer 

 and self-complacent expounder, the learned William Swainson.^ 



" The Ilora? Entoniologica\^ unluckily for students, can only be thoroughly 

 imderstood by the ade2)t, since the results and observations are explained in different 

 parts; the style is somewhat desultory, and the groups, for the most part, are rather 

 indicated than defined. The whole, in short, is what it professes to be, more a 

 rough sketch of the leading peculiarities of the great divisions of animals, and the 

 manner in which they are probably connected, than an accurate determination of 

 the groups themselves, or a demonstration of their real affinities. More than this, 

 perhaps, could not have been expected, considering the then state of science, and 

 the herculean difficulties which the author had to surmount. The work in ques- 

 tion has now become exceedingly scarce, and this will be an additional reason 

 with us for communicating occasional extracts from it to the reader. Mr. McLeay's 

 theory will be best understood by consulting his diagram ; for he has not, as we 

 have already remarked, defined any of the vertebrated groups. Condensing, how- 

 ever, the result of his remarks, we shall state them as resolvable into the foUowingr 

 propositions : 1. That the natural series of animals is continuous, fonning, as it 

 were, a circle, so that, upon commencing at any one given point, and thence 

 tracing all the modifications of structure, we shall be imperceptibly led, after passing 

 through numerous forms, again to the point from Avhich we started ; 2. That no 

 groups are natural which do not exhibit such a circular series; 3. That the 

 primary divisions of every large group are ten, five of which are composed of 

 comparatively large circles, and five of smaller: these latter being termed osculant, 

 and being intermediate between the former, which they serve to connect; 4. That 

 there is a tendency in such groups as are ^^hiced at the opposite points of a 

 circle of affinity 'to meet each other;' 5. That one of the five larger groups 

 into which every natural circle is divided, 'bears a resemblance to all the rest, or, 

 more strictly speaking, consists of types which represent those of each of the four 

 other gronp.s, together with a type peculiar to itself These are the chief and 

 leading principles which Mr. McLeay considers as belonging to the natural system. 

 We shall now copy his diagram, or table of the animal kingdom, anil then endeavor, 

 with this help, to explain the system more in detail." 



' SwMNsoN, (W.,) A Treatise of the Geogrnpliy ^ McLeay, (W. S.,) Ilonu EntoiuologicjE, or 



and Classifiealion of Animals, London, 1835, 1 vol. Essays on the Annulose Animals, London, 1819-21, 



12mo., p. 201-205. 2 vols. 8vo. 



28 



