36 
instead, a number of cupules which may be either stalked . 
or sessile. 
Phyllocotyle gurnardi, van Beneden and Hesse. 
On the gills of the common gurnard, Trigla gur- 
nardus, and yellow gurnard. A small species and easily 
overlooked. Three pairs of sessile cupules. 
Microcotyle labracis, van Beneden and Hesse. 
On the gills of the “bass,” Labrar lupus. A 
moderately large species with a number of sessile cupules, 
but not common on any of the fishes examined by us. 
Octobothrium scombri (Kuhn). 
On the gills of the common mackerel. A very slender 
species and easily overlooked. Four pairs of sessile 
cupules. 
Octobothrium merlangt (Kuhn). 
On the gills of the whiting. A large species of a dark 
colour. Four pairs of cupules on short stalks. 
Dactylocotyle pollachi, van Beneden and Hesse. 
On the gills of the pollack. A large species of a 
dark colour. Four pairs of cupules on moderately long 
stalks. 
I11.—Species with cupules, and a bifurcated median 
appendage :— 
Onchocotyle appendiculata (Kuhn). 
On the gills of various Elasmobranch fishes (rays and 
dogfishes), sometimes very common. ‘Three pairs of large 
cupules and a slender appendage, bifurcate at the apex. 
In addition to these Trematoda one representative of 
the Hirudinea is known from the Ivish Sea fishes. The 
large skate leech, Pontobdella muricata, Leach, with its 
corrugated, warty skin, is often found on rays captured 
by the fisheries steamer, 
