184 MR. W. A. FORBES ON THE KOALA. [Jan. 18, 



globular, and therefore less cj'lindrical in shape, the cardiac and 

 pyloric openings being more approximated. 



The small intestine is villous, but otherwise smooth. It is not 

 sacculated, and when spread out, after being cut, is 0'5 inch across. 

 At its commencement it is dilated for about two inches ; there are no 

 Peyer's patches ; its length is 1 15 inches. The large intestine is 

 very peculiar : for the first 28^ inches or so of its length, which forms 

 the ascending colon, it is very capacious, and internally longitudinally 

 corrugated, like the caecum, which externally it much resembles, the 

 rugae of the interior appearing through the walls of the intestine, 

 and giving it a longitudinally striated appearance. These folds of 

 the mucous membrane, which might be called longitudinal valvules 

 conniventes, where best developed are about "2 inch in depth ; they 

 are arranged longitudinally and are roughly parallel, though some- 

 what irregular in extent ; they are separated from each other by 

 intervals of about the same extent (0"2 inch). At the commence- 

 ment of the colon, which here, when cut open and spread out, is 

 3' 75 inches broad, and of the cfecum, there are about a dozen of 

 these folds very well marked. These continue throughout tbe 

 ascending, csecum-like, colon ; but where it narrows to form the 

 transverse and descending parts they converge, and become more or 

 less blended with each other, forming linear elevations. They are 

 continued downwards as far as the rectum, but are reduced by that 

 time to five'. In the caecum, which is also very capacious, the same 

 arrangement of folds obtains till within 18 inches of its apex, when 

 they gradually disappear, the rest of the organ being thence onwards 

 quite smooth internally. The caBCum, the curious position of the 

 caput oi which has already been described, measures 46"75 inches in 

 length (nearly three times the length of the animal's body !) ; the large 

 intestine 93-25 inches. In an adult female (20g inches long), pre- 

 served in spirit, the following were the intestinal measurements : — 



inches. 



Small intestine 1 11-15 



Large „ 160-8 



Caecum 660 



Owen (Anat. Vert. iii. p. 420) gives 92, 125, and 77 inches 

 respectively. On each side at the junction of the ileum and colon 

 is a small patch of three glands. 



The liver of the Koala is of very remarkable form. It is repre- 



^ Mr. Martin describes {I. c. p. Ill) both colon and cacum as sacculated "by 

 a slight longitudinal (mesenteric) band of muscular fibres," with indications of 

 a similar opposite baud. I could find no traces of any such sacculation in the 

 fresh Koala examined by me ; nor are they mentioned by Prof. Owen (Anat. 

 Vert. iii. p. 418). It is also to be noticed that Martin does not in any way 

 allude to the existence of the very remarkable folds of the interior of the caecum 

 and colon. 



In Phcdangisia and Phascohmys an examination of fresh specimens has com- 

 pletely failed to exhibit any traces in either ereeum or colon of the longi- 

 tudinal folds here described. In the latter genus the colon is capacious at ts 

 commencement, and sacculated transversely, in a way that does not obtain iu 

 either Phalangista or Phascolarctos. 



