ON THE ANATOMY OF THE KOALA. 177 



separated from each other by intervals of about the same extent (O2 inch). 

 At the commencement of the colon, which here, when cut open and 

 spread out, is 3*75 inches broad, and of the caecum, there are about a 

 dozen of these folds very well marked. These continue throughout the 

 ascending, caecum-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 down- 

 wards 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 caecum, the curious position of the caput of 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 (20| inches long), preserved in spirit, the following were the 

 intestinal measurements : 



inches. 

 Small intestine 111-15 



Large 160-8 



Crccum 66-0 



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 represented, 

 drawn to scale of |- the natural size, in the accompanying figures (1 and 2, P. Z. S. 1881, 

 pp. 178, 179). All four principal lobes are well developed ; but those p< 185< 

 on the right are far larger than those on the left, the left central being 

 considerably the smallest of these. The umbilical fissure is distinct, 

 extending about halfway across the liver. The right central lobe, which 

 is broad transversely, and forms the largest lobe, is divided very deeply 

 by the large cystic fissure, which extends on the thoracic surface nearly 

 as far back as the umbilical one, and allows the very large and elongated 

 gall-bladder to appear above. Both right and left lateral fissures are also 



* Mr. Martin describes (1. c. p. Ill) both colon and caecum as sacculated "by a 

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

 opposite band. 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 Phalangista and Phascolomys an examination of fresh specimens has completely 

 failed to exhibit any traces in either caecum or colon of the longitudinal folds here 

 described. In the latter genus the colon is capacious at its commencement, and 

 Bacculated transversely, in a way that does not obtain in either Phalangista or 

 Phascolarctos. 



