324 
Entozoci of Fishes 
fishes have been examined without a single specimen of that parasite 
being obtained, whereas almost all the littoral fishes are infected with 
it. In the enclosed waters of the Firth of Clyde, however, additional 
hosts in the shape of Gadus virens, Gadus pollachius and Pleuronectes 
limanda presented themselves. These were all young fish and were 
captured close inshore. Whether or not they rid themselves of the 
parasite when they leave the inshore waters and grow to maturity 
I have not been able to ascertain, but it certainly has not been found in 
any of the few adult specimens of saitlie or pollack which I have had an 
opportunity of examining. From this the conclusion which may with 
justice be drawn, is that Podocotyle atomon is essentially an inshore 
form and that its cercaria encysts in some littoral invertebrate. In 
connexion with this species another point which I was enabled to 
confirm, is the fact that although plentiful in the salt-water stickleback 
(Gasterosteus aculeatus var. trachurus ) it does not occur in the fresh-water 
variety (var. gymnurus). 
Of the 29 species of fishes obtained, 17 had already been examined on 
the East coast, seven have since been examined, while the remainder were 
only met with on the West. The latter however were mostly isolated 
individuals and the only typically western fish which was examined in 
any number was Labrus berggylta. Elasmobranchs were not dealt 
with. Amongst the Teleosteans only two Lophobranchs ( Syngnathus- 
acus and Nerophis lumbriciformis) were examined and they yielded no 
parasites. 
Infection on the whole reached almost the same degree as on the 
East coast. 80 °/ 0 of the total number of fish examined were infected 
with helminths of one or more kinds. Most numerous amongst these 
were Nematodes which were present in 76°/o> Trematodes were found 
in 70 °/ 0 , Cestodes in 46°/o and Echinorhynchi in 13 °/o* In the case 
of Nematodes however, in only a little over 4°/o were they found in 
the alimentary canal. Almost a third of the fishes harboured immature 
or larval Nematodes in their body cavity or encysted in the peritoneum. 
The great preponderance of Cestode infection was in the form of 
scolices, chiefly Scolex polymorphic, which occurred in 17 °/ 0 . Only 
about 6°/o were infected with adult tapeworms. This agrees very 
closely with the figures found at St Andrews and we may therefore 
take it that tapeworms are the most uncommon form of parasite in 
marine Teleostean fishes. This has also been noted by Linton (1910) 
in the case of American fishes. 
By far the commonest parasite was undoubtedly Podocotyle atomon 
