64 CONTRIBUTIONS TO AMERICAN HELMINTHOLOGY. 
The general outline of the body is somewhat oblong when the worm 
is at rest; in motion, however, its form is capable of considerable 
variation, and it is especially then that the constriction corresponding 
to the position of Zeller’s “Seitenwiilste” is noticeable. The caudal 
lamina is somewhat narrower than the greatest width of the body, 
and is shorter than it is broad. The body narrows considerably at 
its junction with the caudal lamina. 
The hooks and suckers are disposed very much as in P. integerri- 
mum. The suckers (0.2 mm. in diameter) seem to project rather 
more than in that species, and their prominent rim bears a series of 
rounded apertures similar to those spoken of above in describing the 
suckers of Octobothrium sagittatum. The smaller hooks (Fig. 11) 
measure 0.015 mm. in length. The six anterior of these are situated 
in pairs between the two anterior suckers. They have a knobbed 
attached end, with an arm (longer than represented in the figure) pro- 
jecting at right angles not far from the middle of the hook. The four 
posterior (situated between the larger hooks) are capable of more 
independent action than the others. This was evident when the 
worm endeavoured to free itself from the piece of thin glass by which 
it was covered. The two large hooks measure 0.15 mm., and have a 
proportionately deeper notch than those of P. integerrimum.” 
No eye-spots were observed in the adult worm. ‘The longitudinal 
system of muscular fibres seemed to be most developed. 
The mouth is transversely oval, and is surrounded by a well-marked 
sucker, in which radial and vertical fibres preponderate. It leads 
immediately into a bowl-shaped pharynx, the walls of which possess 
merely weak circular fibres, and from this the simple intestinal coeca 
arch backwards directly. The coeca of all the observed specimens 
were empty. 
Only the convoluted lateral stems of the water-vascular system 
were observed near the anterior end. 
The lobes of the vitellogen are more scattered than in P. integerri- 
mum, and do not extend into the caudal lamina. The transverse 
duct seemed to pass inwards dorsally from the intestinal coeca ; but I 
have been unable to determine the relationship of the internal genera- 
tive organs, partly from the fact that my specimens were taken from 
the turtle the day after it was killed, and consequently had very little 
vitality. 
22 Of. Zeller, loc. cit., Taf. XVII. p. 12. 
