244 
Treniatodes from Fish 
parasite. Along with this new species there occurred a small number 
of specimens of Derogenes various. 
It is a rather small form, mature specimens measuring only 
0'6-0'9 mm. in length. 0'6 mm. appears to represent its minimum adult 
length as all the specimens below that were immature. Its shape is 
elongated, sub-cylindrical with rounded ends. The greatest breadth in 
an average specimen (0'73 mm. long) is 0T8 mm. The breadth, however, 
is fairly uniform. The cuticle is smooth and unarmed. 
The oral sucker is subterminal with a small fleshy lobe projecting 
in front of it. It is globular with a diameter of 0 066 mm. The ventral 
sucker is also globular with a diameter of 0T23 mm. It lies 0 34 mm. 
from the anterior end, i.e. a very little in front of the middle of the body. 
Contiguous with the oral sucker is a moderately large pharynx, 
measuring 0'039 mm. in diameter. The oesophagus is short and in no 
case longer than the pharynx. The intestinal diverticula are simple 
and fairly straight, reaching almost to the posterior end of the body. 
The excretory vesicle resembles that in Derogenes, the unpaired 
median stem dividing some distance behind the ventral sucker (between 
the testes) aiid the paired limbs uniting dorsal to the pharynx. 
The disposition of the genital glands also resembles that in 
Derogenes, the testes being approximately symmetrical with a slight 
tendency to obliquity. They are separated from the ventral sucker by 
a space of about 0 04 mm. and measure 0T2 x 0'096 mm. Their axes 
are oblique, the anterior pole in each case being directed outwards. 
Immediately behind the testes lies the large transversely oval ovary, 
the dimensions of which are 0 07 x 012 mm. Behind this again lie 
the globular yolk glands, which are practically symmetrical. In front of 
the ovary and between the posterior ends of the testes lies a small 
receptaculum seminis. The shell gland complex is situated on the 
dorsal side of the ovary. 
The uterus is not very voluminous and contains only about 40 eggs. 
These are situated for the most part behind the yolk glands. The 
terminal part of the uterus passes up between the testes, over the right 
side of the ventral sucker and unites with the proximal end of the 
cirrus pouch. The eggs differ from those of Derogenes in having the 
anopercular pole drawn out into a sharp point. In their passage through 
the uterus the pointed end is always directed backwards. They measure 
0'033-0 042 X 0 015-0‘019 mm., the average being 0'038 x 0 018 mm. 
The terminal part of the male organs bears a general resemblance 
to that of Derogenes but differs from it in detail. It is in the first place 
not so elongated, the vesicula seminalis being small and globular. The 
