﻿EXTERNAL ANATOMY. BILL. 



63 



serrated, for the purpose of cutting away the outer 

 leaves of the heads of plants, in order to get at those 

 which are the youngest and most tender. Mollini, who 

 vouches for this fact, goes on to assure us that these 

 birds are consequently very destructive to the farmer ; 

 and we can readily suppose that a few of them would 

 very soon destroy a field of Indian corn before the 

 heads had burst or come to perfection. It is probable 

 that the teeth of the toucan is of essential service in 

 crunching and breaking the bodies of the small birds 

 which it captures, and which are reduced to a shapeless 

 mass before it is tossed up in the air and swallowed. 

 The only example we are acquainted with of an in- 

 cessorial bird having a central or raptorial tooth to its 

 bill, is the Lanio of Vieillot (fig. 28. e), a bird which 

 obviously belongs to the tanagers, notwithstanding this 

 anomalous formation. 



(58.) We may now consider the bill in regard to 

 its figure ; that is, its length, breadth, and direction. A 

 bill is called short, when its length does not equal the 

 space between the nostrils and the nape of the neck 

 (fig. 30. a) ; it is then said to be shorter than the head : 

 when these two parts are equal, the bill is termed mo- 

 derate (b) ; but when it exceeds the length of the head, 



adopt this plan, because it is in general use, although the 

 latter mode of measurement is certainly more strictly 

 correct than the former. According to these views, the 

 shortest billed birds become those which have the widest 



it is designated as long (c). Its 

 circumference assumes three 

 principal forms ; for it is either 

 compressed, depressed, or round. 

 The length of a bill is usually 

 estimated from that part which 

 protrudes beyond the front of 

 the head ; and not, unless so 

 expressed, from the angle of 

 the mouth to the tip of the 

 upper mandible. We shall 



