1902,] ADAPTATIONS IX DIPROTODOXT MARSUPIALS. 19 



The digestion in the ceecum seems to be rather complete, since 

 at a distance of 25 cm., more or less, from the ileo-ctecal valve the 

 fascal matter is already formed into balls. A microscopical 

 investigation of these ffecal remains shows that they are chiefly 

 composed of pieces of thick- walled epiderm, bundles of vessels, 

 isolated prosenchy me- cells, and similar matter. But the softer 

 vegetable tissue has disappeared and the spiral thi-eads of the 

 vessels are isolated, indicating a digestion of the substance that 

 once formed the walls. 



The intestine of the Koala has been described, as already 

 mentioned, by the authors quoted above. Only a few remarks 

 will therefore be made here concerning the intestine of a 

 marsupial foetus of this species measuring about 9 cm. in length. 

 Its smallintestine measured about 37 cm., the csecum 8-5 cm., and 

 the large intestine about 29 cm. The length of the three different 

 parts of the intestine, compared with the length of the fcetus 

 itself, is thus expressed by the following percentages: 411, 94, 

 322. If these now are compared with the corresponding ones 

 from a grown animal, calculated from Forbes's measurements 

 (see above), the difference is quite striking with regard to the 

 caecum and the large intestine. The former is proportionately 

 only about a third as long in the foetus as in the full-grown 

 animal, and the latter less than half as large in the foetus as in 

 the adult. The difference of the small intestine of both stages is 

 not so great, that of the foetus being about four-fifths of the same 

 in the adult. It is also to be remarked that in the foetus the 

 small intestine is considerably longer than the colon, but in the 

 adult the reverse condition prevails. These differences can of 

 course be ascribed to the difference of the diet of both stages. 

 The milk food of the foetus is chiefly or completely digested in 

 the small intestine, but the vegetable diet of the adult needs a 

 greatly developed cpecum and colon. The longitudinal folds of 

 the caecum and the colon are, however, already developed in the 

 foetus. 



The condition found in the Wombat is very peculiar. The 

 narrow opening of the ileum protrudes, surrounded by an " ileo- 

 cgecal " valve, into the colic cavity. This valve has very broad 

 lips, and within the same opens the lumen of the " processus 

 vermiformis" (Owen), only separated from the opening of the 

 ileum by a septum — that is, in other words, the terminal portions 

 of the vermiform appendage and of the ileum are thus fused 

 together into one structure protruding into the colon ; both open 

 with separate orifices, which are, however, surrounded by the lips 

 of the same valve. The glandular patch described above as 

 situated near the valvida cceco-coUca in the related Phalangerids 

 is found in this animal too, but extends partly on to the outer 

 side of the " ileo-caecal " valve itself already mentioned. From 

 this latter valve plicae extend on two sides. These plica3 seem to 

 stand in the same kind of connection to the ileo-caecal valve as in 

 normal cases the caeco-colic valve does. But they do not extend 



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