32 DICTIONARY OF BIRDS 



Nieremberg, extended his figure of speech, and, while justly deprecating 

 the notion that the series of forms belonging to any particular group of 

 creatures — the Mammalia was that whence he took his instance — could be 

 placed in a straight line, imagined the various genera to be arrayed in a 

 series of contiguous circles around Man as a centre. Though there is 

 nothing to shew that Fischer intended, by what is here said, to do any- 

 thing else than illustrate more fully the marvellous interconnexion of 

 different animals, or that he attached any realistic meaning to his 

 metaphor, his words were eagerly caught up by the prophet of the new 

 faith. This was William Sharpe Macleay, a man of education and real 

 genius, who in 1819 and 1821 brought out a work under the title of 

 Horx Entomologicse, which was soon after hailed by Vigors as containing 

 a new revelation, and applied by him to Ornithology in some " Observa- 

 tions on the Natural Affinities that connect the Orders and Families of 

 Birds," read before the Linnean Society of London in 1823, and after- 

 wards published in its Transactions (xiv. pp. 395-517). In the following 

 year Vigors returned to the subject in some papers published in the 

 recently established Zoological Journal, and found an energetic condisciple 

 and coadjutor in Swainson, who, for more than a dozen years — to the 

 end, in fact, of his career as an ornithological writer — was instant in 

 season and out of season in pressing on all his readers the views he had, 

 through Vigors, adopted from Macleay, though not without some modi- 

 fication of detail if not of principle. What these views were it would be 

 manifestly improper for a sceptic to state except in the terms of a 

 believer. Their enunciation must, therefore, be given in Swainson's own 

 words, though it must be admitted that space cannot be found here for 

 the diagrams, which it was alleged were necessary for the right under- 

 standing of the theory. This theory, as originally propounded by 

 Macleay, was said by Swainson in 1835 {Geogr. and Classific. of Animals, 

 p. 202) to have consisted of the following propositions :^ — 



" 1, That the series of natural animals is continuous, forming, as it were, a circle ; 

 so that, upon commencing at any one given point, and thence tracing aU the 

 modifications of structure, we shall be imperceptibly led, after passing through 

 numerous forms, again to the point from which we started. 



" 2. That no groups are natural which do not exhibit, or shew an evident tend- 

 ency to 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 placed 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 groups, together with a type peculiar 

 to itself.' " 



As subsequently modified by Swainson {torn. cit. pp. 224, 225), the 



foregoing propositions take the following form : — 



^ I prefer giving them here in Swainson's version, because he seems to have set 

 them forth more clearly and concisely than Macleay ever did, and, moreover, Swain- 

 son's application of them to Ornithology — a branch of science that lay outside of 

 Macleay's proper studies — appears to be more suitable to the present occasion. 



