4.04 WILLIAM NICOLL. 
A word must be said here with regard to the dimensions 
of the suckers as stated by Olsson. Considerable discrepancy 
exists, which necessitates an attempt at explanation. The 
sizes given by Olsson are ‘40-52 mm. for the oral sucker and 
°63—75 mm, for the ventral sucker. These are evidently 
much in excess of my measurements and cannot apply to a 
specimen of 3-4 mm. in length, Olsson says they were 
measured from a “spec. adult,’ and by this he must under- 
staud a specimen of 5-6 mm, in length. On this supposition 
the oral sucker. would be about one eleventh of the body 
length and the ventral sucker about one eighth. Moreover, 
on careful measurement of Olsson’s figure I find that the 
suckers are respectively one eleventh and two fifteenths of 
the body length. According to Linton also the oral sucker 
is one eleventh and the ventral sucker one eighth. In view of 
this agreement it may be taken as a distinctive feature of the 
species that the oral sucker is one twelfth to one eleventh and 
the ventral sucker one eighth to one seventh of the body 
length. 
The cuticle has a fairly uniform thickness of ‘0025-003 mm. 
The musculature of the body conforms to the usual type, 
with the three subcutaneous layers, circular, longitudinal, 
and diagonal, and the less organised parenchymatous fibres. 
Close underneath the layer of diagonal muscle-fibres hes a 
layer of what were formerly regarded as cutaneous glands, 
but which are, according to Bettendorf,’ the myoblasts of the 
subcutaneous muscle-fibres. So far as can be gathered, 
Bettendort’s views have not been completely confirmed, but 
they are probably correct. At any rate the glandular nature 
of these cells has never been proved, and from Bettendorf’s 
work they appear to be in intimate connection with the sub- 
cutaneous muscle-fibres. These cells, as I have observed 
them in this species, stain deep blue with heemalum-eosin and 
the nuclei are only differentiated by being denser. The cells 
are rounded in outline with several filaments, and in many 
cases they appear fused together in groups of two or three, 
1 ¢ Zool, Jahrbuch, Abth, Anat.,’ x, 1897, p. 307, 
