4.64. WILLIAM NICOLL. 
the body the cuticle does not display the same wrinkling, 
and it is not present on the dorsal surface of the body. The 
little rod-like bodies follow the course of these wrinkles, as 
do also the circular subcutaneous muscle-fibres. ‘The longi- 
tudinal muscles, however, do not; their course is straight 
and it is evidently to their action that the wrinkling is due. 
The diameters of the circular, longitudinal and diagonal 
muscle-fibres are respectively about ‘0015 mm.,°005 mm. and 
‘004 mm., and the spaces separating them are on an average 
°0035 mm., ‘007 mm. and ‘008 mm. in the three cases. The 
angle made by the diagonal fibres is about 155°. The 
myoblasts in connection with these fibres are quite as numerous 
as usual. 
The true subcutaneous glands are large and numerous ; 
they occur only on the ventral surface, but they are not 
confined to the anterior part of the body as is the case in 
most species... A considerable number are to be found 
behind the ventral sucker, but they cease about the middle 
of the post-acetabular region. They measure about °045 by 
‘03 mm.,and are rounded, oval in outline with highly granular 
contents and small eccentric nuclei, ‘O07 mm. in diameter. 
Alimentary System.—There is a short pre-pharynx, in 
the wall of which well-marked circular and longitudinal 
muscle-fibres are present. ‘The pharynx has a length of 
‘16-21 mm.; its breadth is usually somewhat less. It appears 
to be more muscular than the suckers, for in addition to the 
usual fibres several equatorial fibres are present. It contains 
very few cells, and these are almost entirely of the myoblast 
type, situated in the middle zone, but much smaller than 
those of the ventral sucker. 
‘here is practically no undivided cesophagus, the bifurca- 
tion taking place immediately behind the pharynx, but the 
initial parts of the diverticula are not lined with intestinal 
epithelium. Hach of these parts is about *-1mm. long and 
‘O04 mm. wide. ‘They are lined by a cuticularised membrane. 
The diverticula are simple wide sacs running nearly the 
whole length of the body, but terminating at the posterior 
