. The American journal of anatomy. -gests an examination of thestages, if stages there be, andof the factors that have beenoperative, in the productionof this extraordinary transfor-mation. Before proceeding with thediscussion of this matter, abrief survey will be made ofthe relations and extents ofthe various portions of thestomach in a number of rep-resentative species of severalorders of Mammalia. In the Monotremata thestomach is lined throughoutby stratitied squamous epithe-lium and is quite devoid ofglands, although a well-devel-oped group of Brunnersglands is found at the pyloricorifice.
. The American journal of anatomy. -gests an examination of thestages, if stages there be, andof the factors that have beenoperative, in the productionof this extraordinary transfor-mation. Before proceeding with thediscussion of this matter, abrief survey will be made ofthe relations and extents ofthe various portions of thestomach in a number of rep-resentative species of severalorders of Mammalia. In the Monotremata thestomach is lined throughoutby stratitied squamous epithe-lium and is quite devoid ofglands, although a well-devel-oped group of Brunnersglands is found at the pyloricorifice. Among the marsupials twotypes of stomach are met with. In the opossums (Fig. 10, A) Dasyures,Bandicoots and Phalangers the stomach is simple, resembling closelyin shape and in the arrangement of its parts those of the insectivorousand carnivorous placentals. A large fundus gland zone occupies thegreater portion of the mucous surface, the rest being occupied by thepyloric glands. The cardiac inland zone is either altogether absent. Figs. 10-16. Diagrams to illustrate the regionsoccupied in different stomachs by the variouskinds of glands. Fig. 10. Stomachs of: A, Didelphys; R, Dorcop-sis; C, Macropus; the two latter after Schiifer andWilliams. Ahhreviatio})><: Ca=cardiac glands; F=fundusglands: P=pyloric glands; ()e=portion of stomachwithout glands and lined by a stratified epithelium. E. R. Bensley 137 • (Phalangista) or occupies an extremely narrow area at the terminationof the wsophagns (Didelphys, Dasynrns, Perameles). The oesophagealepithelium does not extend into the stomach. In the kangaroos, on the other hand, a highly complex condition ex-ists. The stomach is elongated intestiniform in shape? and exhibitspeculiar colon-like sacculations. The oesophageal epithelium extendssome distance into the stomach and a considerable cardiac gland zone ispresent. As a result of these important modifications, the fundus andpyloric glands are confined to a small portion of the
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1901
