THE STRUCTURE OF CRYPTOGONIMUS 
527 
The posterior end of the oesophagus lies immediately under the 
dorsal surface. The two intestinal coeca arise directly from it 
and pass obliquely backward as shown in fig. 2. They run down- 
ward as far as the vitellaria, not passing into the posterior end 
of the animal. In the encj'sted stage (see fig. 7) they are rela- 
tively longer and reach almost to the posterior end. ^lost of 
the intestinal coeca lies in the level indicated in the schematic 
cross section, fig. 4. Each coecum is a strictly simple tube, whose 
epithelium is low and flat as shown both b}' the boundary line 
of the inner wall and b}' the widely separate nuclei. In no case 
have I seen any tall epithelium cells in the intestinal epithelium 
or an}^ boundaries between the cells. 
Favorable longitudinal sections in several different series show 
a longitudinal musculature in the wall of the intestine. This is 
composed of a very few widely separated fibres, fig. 4. Such 
fibres can be recognized in all parts of the organ but in no case 
has it been possible to demonstrate the presence of an}^ circular 
fibres. 
Usually no food was visible in the cavities of the alimentary 
organs, but in some worms the oral sucker and prepharynx were 
filled with minute granular material which, under the highest 
magnification and favorable illumination, proved to be made up 
throughout of objects which, when stained with borax carmine, 
present a flat rounded unstained portion lodging a deeply stained 
nucleus or a mass of small deeply stained particles which can be 
considered a disintegrated one. Though I have no complete 
proof to present, there seems little reason to doubt that these are 
blood corpuscles. In the encysted specimens from which fig. 7 
was drawn the intestine was filled as far forward as the level of 
the ventral sucker from the posterior end with small rounded 
objects. 
EXCRETORY SYSTEM 
The excretory system, so far as I have succeeded in determining 
its anatomical structure, is exceedingly simple. There is a ter- 
minal pore, fig. 3, located as usual, from which a slender short pas- 
sage runs forward to reach the end of a rather large posterior 
