334 PHACTICAIi AND SCIENTIFIC ZOOLOGY. 



group should receive stronger verification; that it should be 

 compared with others of its own order, and finally with 

 one of its own rank ; as, for instance, with the family of 

 shrikes {Laniadce Sw.), and these comparisons are to 

 be instituted on precisely the same principles as those 

 we have just exemplified. If, therefore, our group will 

 bear all these comparisons, and if the same analogical 

 results follow, and in the same order, we may then be 

 assured that our circle is a true one. And if, to " make 

 assurance doubly sure,'' we can extend our comparisons, 

 and detect the same analogical resemblances in other 

 groups belonging to different classes of animals, we 

 not only demonstrate our arrangement of the Merulidw 

 with almost mathematical certainty, but we pile ac- 

 cumulated proofs upon the thoretical assertion that there 

 is but one uniform plan of variation throughout nature. 

 (410.) The student wiU now see the worthlessness 

 of aU assumed circles of affinity which have not been 

 put to these necessary tests, and which merely repose 

 on the assertion of their inventors. This, in short, has 

 been the rock upon which some of the warmest advo- 

 cates of this theory have split. While, from the fallacy 

 of their circles having been detected, occasion has been 

 given to shallow reasoners to throw doubts upon one of 

 the greatest truths in natural science ; truths, in fact, 

 of which such persons have only a partial knowledge, 

 by judging of their value from their mistaken appli- 

 cation by zealous but ill-informed advocates. The 

 family of Merulidce, no doubt, might be arranged 

 in two or three circular ways, each of which, if their 

 analogical resemblances to other groups are dispensed with, 

 would appear to be just as natural as the one here given ; 

 for we have tried the experiment. Yet the moment 

 these assumed circles are brought up for verification, 

 their falsity is at once demonstrated, by their discordance 

 with authenticated circles. Hence the student will see 

 the reason of our former remark, that false circles of 

 aflSnity can be made with every appearance of being 

 natural; and that these will " pass muster" with all those 



