10 DR. F. E. BEDDARD ON 
unreasonable to suppose that there are variations in the degree of | 
progress of the reduction of this cavity. As before, the cavities A . 
and C are chiefly at the two ends of the worm. iy 
Text-figure 6. 
Longitudinal section through larva figured in text-fig.1, D. 
d.v. Dorsal water-vascular tube coiled and therefore seen cut across in several places. 
thie m. Longitudinal muscles. 
Other lettering as in text-figs. 2 & 5. 
The water-vascular system (spaces lettered d) is more fully 
developed in this older plerocercoid, and it differs from that of the 
younger example in the presence of a perfectly distinct dorsal vessel’ 
