. The structure and classification of birds . ne; the whole of its course isdisposed into six specialised loops. The owls and the Capri-mulgidse appear, according to Mitchell, to have preservedmuch of the primitive short, convoluted loops of the lowerbirds, and so, though to a less extent, has Gorythaix. Thevery short intestine of the Passeres, represented here by Parusmajor, is not so easy to understand, but its general appearanceis that of a primitive gut. Some further details will be foundin the succeeding chapters, under the different families towhich they refer. The csBca lie at the comme
. The structure and classification of birds . ne; the whole of its course isdisposed into six specialised loops. The owls and the Capri-mulgidse appear, according to Mitchell, to have preservedmuch of the primitive short, convoluted loops of the lowerbirds, and so, though to a less extent, has Gorythaix. Thevery short intestine of the Passeres, represented here by Parusmajor, is not so easy to understand, but its general appearanceis that of a primitive gut. Some further details will be foundin the succeeding chapters, under the different families towhich they refer. The csBca lie at the commencement of the large intes-tine, which indeed can be, as a rule, only differentiated fromthe small intestine by the break thus caused. This is, how-ever, not invariably the case, for in Struthio (see fig. 12, p. 28)there is a distinct break between the two sections of thegut, quite independent of the cseca, which can be readilyseen from an inspection of the figure cited. The cseca areamong the most variable organs of birds. Not only are they. ALIMENTAEY CANAL 31 sometimes completely absent, as in the majority of that large assemblage of birds the picarians, but when present they show every degree of relative size. In the Passeres, and in some other birds, the two caeca are the merest nipples, which cannot be believed to serve any function. They are in the same way reduced in size in the hawks and storks. On the other hand, in the galhnaceous birds, in the Limicolae, and in some others the cseca are large tubular. diverticula of the gut, the length being sometimes to be measured by inches. Among the owls the cseca are large, and have the Fig. is.—Pai-us major. additional peculiarity of being (fdli:S.!iZc^^Z swollen at the blind extremity. The caeca are most complicated in the ostrich, the screamers, and the tinamou Calodromas, under the descriptions of which birds will be found an account of this organ. The herons are remarkable for the fact that one of the two cseca has disap
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
