( 400 ) 



primary loop of the intestine to the vitelline caecnm, whichis at its middle. This 

 vein, however, is borne at the snmrait of a deep fold of mesentery for the greater 

 part of its course. Towards the vitelline caecnm this fold becomes obsolete. 



As to the length of the intestine, I measured it in three individuals belonging 

 to the species A. auatralis, A. haagti, and A. oweni, which were about of the relative 

 sizes that is indicated by the order of their placing — A. australis being the largest 

 individual. I found the lengths of the entire gut and of the caeca to be as 

 follows : — 



The measurements, corresponding so nearly as they do, did not seem to favour 

 the probability of discovering specific diiferences by the study of a more extensive 

 series. 



I do not find myself able to agree in every detiiil with Sir R. Owen's description 

 of the lining membrane of the intestine. He writes that the duodenum is beset 

 with extremely fine villi about one line in length which are towards the end of the 

 duodenum converted into thin zigzag longitudinal folds. At the very beginning of 

 the duodenum (of A. oweni) I find appearances a little diflerent : there are, in fact, 

 no separate villi at all, but closely set zigzags, which give a beautifully sculptured 

 appearance to the interior of the gut. In the lower part of the small intestine, not 

 far from the origin of the caeca, these folds are rather more regular, closer, straighter 

 and finer. 



The character of the lining membrane absolutely changes at the origin of the 

 caeca. Moreover, a marked valvular fold separates the small from the large 

 intestine. The latter has a series of conspicuous longitudinal ridges ; these, for the 

 most part, cease some little way in front of the end of this portion of the gnt. The 

 appearances of the interior of the gut, however, are liable to alteration from the con- 

 dition of its distension. In the large intestine of A. occidentalis 1 did not find 

 the longitudinal folds referred to except at the very end of that portion of the gut. 



The gall bladder is known, from the investigations of Owen, to be subject to 

 individual variation. It was wanting in one of the three individuals dissected by 

 him. Mr. W. A. Forbes (MS. notes) found a gall bladder in a specimen each of 

 A. australis and ^1. oweni. 



In a sjiecimen of A. kaasti, dissected by myself, there was a large gall bladder ; 

 but the mode of its connection with the liver and with the cystic and hei)atic ducts 

 'Was difierent from that figured by Owen. The cystic duct leaving the gall liladder 

 was immediately joined by a duct from the right lobe of the liver, and then became 

 continuous by means of a branch with the hepatic dnct coming from the left lobe. 

 A second specimen had an eijually well developed gall bladder. 



1 found a gall bladder in the remaining species, including A. occidentalis. 



4. WINDPIPE. 



The syrinx of Aptenjx has been to some extent described by the late 

 Mr. W. A. Forbes. His observations (illustrated by two cuts) related to the 



