522 HENRY LESLIE OSBORN 
are two muscular organs, each one possessing the structure found 
in the suckers of distomes. These relations are shown in fig. 3, 
also in greater detail in fig. 5. The suckers are not, strictly 
speaking, external organs in this case. A more detailed account 
of them will be given below in connection with the accounts of 
the internal organization. 
The genital opening is located inside this sheath in the mid line 
of the body between the two ventral suckers, (see fig. 1, gyo, also 
fig. 3). In the latter the course of the outer end of the genital 
duct is shown running down between the two suckers. 
The excretory opening is located at the extreme posterior end 
of the body as usual. 
The bod}^ wall is extremely spinous throughout. The spines 
are very conspicuous in living specimens viewed in favorable 
lights, and give the animal almost a shaggy appearance. They 
are so broad in their anterior margins that they may almost be 
designated scales, each one has a short basal piece inserted in the 
cuticle carrying an outer triangular portion whose base lies in 
the transverse axis of the body. The spines lose their broadened 
form posteriorly and have more the hook form, as in trematodes 
at large. They are deeply stained in all iron haematoxylin prep- 
arations while the cuticle is entirely uncolored. 
There are certain internal structures attached to the body wall 
by one end and extending freely posteriorly from this point of 
attachment. Following the designation of other writers for sim- 
ilar structures found elsewhere in this group {e.g., D, clavigerum, 
[Looss '94] fig. 30) I will call these organs glands. In life they 
can be seen as highly refractive objects swaying to and fro with 
the movements of the body, evidently entirel}^ free except at the 
cuticle connection. These glands (shown in fig. 1) lie in trans- 
verse rows girdling the body and extending only as far back as 
the level of the beginning of the posterior third of the animal. 
In sections these glands display their attachment at the surface 
and the rest of the gland extends freely into the interior of the 
body. 
The body wall musculature is rather feebly developed. In 
worms mounted whole under most favorable illumination the 
