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THE AMERICAN NA TURALIST. [Vol. XXXVII 1. 



ever, that \vc will never arri\e at the true and natural classifica- 

 tion of birds, throu-h the employment for that purpose of any 

 sino-lc ,i! of mon)holog-ical characters. 



wa> toward an understanding of their vai ious alliances and rela- 

 tionships ; this is i)arlicularly the case on account of what is to 

 be derived from avian palaontology, — the bones being, with 

 few exceptions, the ]xn-ts preserved. It is extremely unsafe and 

 dangerous to the science of this subject, however, to thus employ 



such knowledge should be modified and corrected by the employ- 



aclers that have been found to exist in the muscular, the arterial, 

 the (Hgestive. the nervous and other systems have proved to be 



A comparative study of the beaks and feet ; the various char- 

 acters presented on the part of the plumage, especially as to 

 color, structure, and style, often constitute admirable checks on 

 a classiticatory scheme of the class based on osteological data. 

 I'ood and other habits when properly studied, and the results 

 applied, are also efficient aids to establishing many of the prim- 

 ary divisions in our scheme ; and a consideration of such data 

 wnhout reterenee to facts of any other kind, is sufficient to 

 enable us to refer a duck, a hawk, or a thrush to their proper 

 places in a taxonomical arrangement. In other particulars nidi- 

 ological and oological studies are of value taken in connection 

 \vith the anatomical and other ones enumerated. Some birds 

 iHiild no nest at all, others construct them of all manner of shapes 

 and sizes and out of all manner of materials. Some birds lav 

 but a single egg. while others may lay a^dozen or more: S(une 



'I'^^l imsp..tled. still others are variously marked or possess other 



comprehended and assorted, mav be emploved in classification 

 with distinct advantage. For example, certam birds possessing 

 an association of osteological characters in their skeletons la\ 

 but two white eggs in an elaborately constructed arboreal nest. 



