PHYLOGENY OF THE PALZOGNATHA AND NEOGNATHA., 249 
degree of divergence of type in the alimentary canal goes, the Ratites deserve their 
accepted place at the bottom of the avian scale.” 
I have been enabled to examine the intestines of all the Palewognathe, save 
Struthio. So far as my material goes it entirely confirms the observations of Gadow, 
Mitchell, and Beddard. 
Casuarius, Dromeus, and Apteryx all resemble one another rather closely. 
In Casuarius and Dromeus the duodenal loop is wide, in Apterye narrow. In 
Casuarius, as Mr. Mitchell points out, the pancreatic and hepatic ducts open into a 
diverticulum of the distal loop. In Dromeus and Apteryse the duodenum is longer and 
narrower, and the pancreatic and hepatic ducts open separately into the duodenum. 
In other genera the small intestine is relatively short, and the convolutions therefore 
are simple. ‘The rectum is short and straight; in Caswarius and Dromeus its inner 
lining is thrown into a number of strongly marked irregular rugous folds. 
In Casuarius and Dromceus the ceca are relatively short, of a uniform thickness 
throughout, and have a narrow lumen. In Apteryx the ceca are relatively much 
longer, exceeding 6 inches in length, whereas in the two former they do not exceed 
5 inches. Furthermore, in Apteryx the terminal half becomes suddenly and markedly 
dilated ; each caecum thus presents a sausage-shaped free end, borne on a narrow tube- 
like stem. 
There are no valvular appendages in the ceca of these three forms. 
Rhea is intermediate between Casuarius on the one hand and Séruthio on the other. 
The duodenal loop is narrow and closed. The convolutions of the small intestine 
resemble Casuarius, the posterior rectal portion Struthio. The pancreatic and hepatic 
ducts open separately. The resemblance to Struthio consists in the relatively great 
length of the rectum ; but it differs therefrom in that it is only thrown into a single, 
and not a series of complex loops. 
The cwca are relatively of enormous length, exceeding those of any other Paleo- 
gnathe. They appear, however, to vary in this respect very considerably. In the 
series of measurements given by Remouchamps [85] the variations in &. macro- 
rhyncha range between 1 foot 42 inches and 2 feet 9 inches; in 2. americana between 
92 feet 4 inches and 4 feet 8 inches. In a female of this latter species dissected by me 
they attained a length of 5 feet 3 inches, accompanying the small intestine throughout 
the greater part of its length. The lumen was sacculated to within a short distance 
of the extreme end of the cecum by means of a series of semilunar valves alternating 
one with another. ‘The position of these valves was indicated on the outside of the 
cecum by means of a series of constrictions (fig. 7, p. 250). 
The intestinal coils of Struthio I have not had the good fortune to examine. I 
therefore append Mr. Mitchell’s description [60]. He writes :—‘ The first two parts 
of the intestine and the three great veins were according to type, the yolk-sac 
diverticulum being conspicuous in the circular loop opposite the end of the median 
