. The structure and classification of birds . t any complicationsof the gut, merely by itsbeing thrown into a series offolds, of which all are moreor less alike. So simple acondition as this does not occur in any known bird. Butthere is more than one type in which this arrangement isretained with but little modification. It is a significant factthat the most primitive arrangement of the folds of theintestine, judged from the crocodilian standpoint, than whichwe have none other more nearly approximating to theprobable reptilian ancestor of birds, is found in birds whichother considerations lead
. The structure and classification of birds . t any complicationsof the gut, merely by itsbeing thrown into a series offolds, of which all are moreor less alike. So simple acondition as this does not occur in any known bird. Butthere is more than one type in which this arrangement isretained with but little modification. It is a significant factthat the most primitive arrangement of the folds of theintestine, judged from the crocodilian standpoint, than whichwe have none other more nearly approximating to theprobable reptilian ancestor of birds, is found in birds whichother considerations lead us to assign a low position in theavian series. In the accompanying drawing (fig. 9) of thescreamer, for example, we have a gut which is but slightlyadvanced from that of the crocodile. The greater part ofthe small intestine shows the same series of undifferentiatedfolds, only the duodenal loop (not missing as a specialisedfold in any bird) being separated off from the general large intestine, however, differs from the short and. Fig. 8.—Alligator Alimentary Tbact (aftee ChalmersMitchell). ALIMENTARY CANAL 27 straight large intestine of the crocodile by its convolutedcourse. So too with the gallinaceous bird (fig. 10), where
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
