of the Family ofAnatidce. 23 



fixed laws, to the test of which every group thought to be 

 natural must be brought. I shall therefore now proceed to 

 demonstrate the accuracy of the foregoing observations, con- 

 densing them into the following tabular form. 



GENUS ANAS. 



Bill longer than the head, depressed nearly its whole length. 

 The base not enlarged, the tip very obtuse ; the laminae of 

 the upper mandible generally projecting. Hinder toe not 

 dilated, short : claws short, thick. Fig. 2, a. 



1. Typical Group, Sutyenera. 



Bill spatulate, simple ; laminae considerably projecting. ANAS. Lin. 



2. Sub Typical Group. 



Bill spatulate, furnished with a lobed membrane ; laminae IM ALACORHY NCHUS Sw 

 considerably projecting. J 



3. Aberrant Group. 

 Bill of equal breadth, projecting laminae short, slender, IQ o 



acute, crowded. J 



Bill more cylindrical, lengthened ; tail long. DAFILA, Leach. 



Bill depressed, of equal breadth ; laminae distant, obtuse, \- Rnaf _ * 

 and generally concealed ; tail short. jtf OSCUAS, Anfcq. 



On proceeding to trace the 



ANALOGIES 



of this genus, I am aware that it would be more satisfactory 

 to compare it with the other groups of the same order and 

 family. But this could not be done without assuming the 

 correctness of the groups themselves, since the natural divi- 

 sions of the Natatores, and the sub-families of the Anatida, 

 rest, at present, upon mere opinion ; they have been predi- 

 cated, but not proved. I must, therefore, content myself with 

 tracing how far the foregoing series partakes of those analogies 

 which belong to the different groups of perching birds ; whose 

 circular affinities I have elsewhere attempted to demonstrate. 

 This comparison, indeed, will be much more difficult than the 

 former, since the strength of the analogies between two given 

 groups is always in proportion to the proximity of these groups 

 in the great scheme of nature. It would scarcely be necessary 

 to advert to this obvious truth, did I not apprehend that some 

 writers, who have as yet given but a superficial consideration 

 to the subject, will pronounce these comparisons altogether fan- 

 ciful. This, however, is not precisely the question. No one 



