150 MR. P, CHALMERS MITCHELL ON THE (Jan. 14, 
down by the remnant of a primitive ventral mesentery. The last 
minor loop of the circular portion of the gut has the long ceca 
running forward alongside it. It is drained in the usual fashion 
by a branch of the mid-mesenteric vein and by short circuit branches 
from the duodenal vein. At first sight there is a striking similarity 
between the gut of the Rails and the gut of Fulmarus (fig. 7, p. 143); 
but this is due simply to the narrowness and regularity of the loops. 
The position of the yolk-duct vestige differs in the two, while the 
short ceca and the kinks immediately above them make absolutely 
distinctive characters in the Petrel. 
In the Dicholophide and the Otidide the Ralline characters are 
still obvious, but the gut is still shorter and the loops more definite. 
Cariama cristata (fig. 14) shows the duodenum and the rectum 
identical with the Rails; the last portion of the circular loop is 
Fig. 14. 
Cariama cristata ; intestinal tract. ., short-circuiting vessel divided. 
identical in its arrangement and veins, although the ceca are still 
larger. The rest of the mid-gut is reduced, the third loop being 
absent. The yolk-duct vestige is in the same place upon the 
second loop, but the first loop of the circular mid-gut is partly 
united with the second. In the Otidide the gut appears to be 
further modified in the direction in which Cariama differs from 
Crex. The duodenum, the rectum, and the last loop of the mid-gut 
are as in the Rails and Cariama ; but the remainder of the mid-gut 
is reduced to a single loop, corresponding to the second of that 
region in Crew, and bearing the yolk-sac vestige on its distal limb. 
CHARADRIIFORMES, 
_ The birds associated in this Order display a very varied series of 
divergences from the type. Among those Limicole that I have 
