116 Part III.— Twenty-third Annual Report 
parallel sides, springs from the rounded end ; this process is armed at the 
extremity with four hooked teeth, the two outer teeth are large and 
strong, with an expanded base, but the other two are smaller and more 
slender (fig. 20). 
According to the authors of the Recherches, this species when extended 
measures about 5 mm., but in the specimen represented by the drawing 
(pl. vi., fig. 19, of this paper), the body is considerably contracted in 
length, and is consequently wider, the peduncle at the posterior end, 
which when fully extended is very slender and narrow, is also shortened 
in the specimen figured. This peduncle is very fragile, and is therefore 
occasionally incomplete, and for that reason, and also because it can be 
folded back under the body of the animal, it may at times easily escape 
being noticed, 
Genus Plectanocotyle, Diesing. 
Plectanocotyle Lorenzi, Monticelli. 
1899. Plectanocotyle Lorenzit, Monticelli, Di una nova Specie del 
genre Plectanocotyle ; Atti. R. Acad. delli Sci. di Torino, 
vol. xxxiv., p. 1, pl. 1 (separate copy). 
1901. Phyllocotyle gurnardi, T, Scott, 19th F.B. Rept., Pt. IIL, 
p. 147, pl. viii , fig. 23. 
A Trematode recorded by me under the name of Phyllocotyle gurnardt 
in the Nineteeth Annual Report of the Fishery Board for Scotland 
(1901), was afterwards recognised as belonging to a species described by 
Dr. F_ BR. Sav. Monticelli two years previously under the name mentioned 
above. 
This Plectanocotyle had been obtained by Dr. Lorenz some years before 
on a species of Gurnard, Z’rigla sp. The slender posterior peduncle, so 
characteristic of Phyllocotyle gurnardi, is apparently absent in Plectano- 
cotyle. The Scottish specimens from Trigla gurnardus were examined 
by Dr. F. R. Sav. Monticelli, and recognised by him as belonging to the 
species he had described in 1899. 
As already pointed out, the peduncle in Phyllocotyle, being so slender 
and fragile, is easily damaged, and when it gets torn off or folded under 
the body, and when the body is shortened by contraction—a contingency 
not uncommon when fishes infested by the parasites are preserved in 
spirit or formaldehyde—the one Trematode may easily be mistaken 
for the other. 
Genus Microcotyle, van Beneden and Hesse (1863). 
Microcotyle donavani, van Beneden and Hesse. PI. vi., fig. 21. 
1863. Microcotyle donavanit, v. Ben, and Hesse, Recherches, 
p. 114, pl. xii., figs. 1-11. 
This species was found on the gills of a Ballan Wrasse (Labrus 
bergylta, Ascan.), obtained by Dr. H. C. Williamson in the Moray Firth 
on October 23, 1904, and also on a Ballan Wrasse captured in the 
North Sea by Mr. Bowman. 
The species is narrow and elongated, and at the posterior end there is 
arow of small suckers along each margin ; the number of suckers in each 
row appears to vary to a small extent. In the specimen represented by 
the drawing (fig. 21) the number in each row is about thirty-four. 
Microcotyle donavani does not appear to be a rare form; the authors 
of the Recherches state that it has been found in abundance on the 
