2 Dr. W. Nicoll on the 



first three eiglit different species of parasites were found, in 

 the cattish seven, and in tiie sprat six. Amongst what may 

 be considered as comparatively rare fish may be mentioned 

 Chi'mcrra 7)ioristrosa, Argentina sphyrcena, and Mvla viola ; 

 and for the o|)|>ortunity of examining these I am indebted to 

 the kindness of Professor Al'lntosh. 



About three-quarters (78 per cent.) of tlie total number 

 oE tisii examined were infected with internal parasites of one 

 kind or another, and of these by far the commonest were 

 Trematodes (G7 per cent.) and Nematodes (65 per cent.). 

 Cestodes occurred only in 45 per cent., and the majority of 

 these were scolices. Adult tapeworms were found in only 

 6 per cent., namely, in the cod, turbot, halibut, and sunfish. 

 Tiie rarity of adult tapeworms was noted in Part I., in which 

 only 8 per cent, of the fishes were infected with them. They 

 ■were found in Cottus scorphis, C. bubalis, Gadus ceglefinus, 

 and Bothus maximus. From this it would appear that tape- 

 worms occur only in the relatively larger fish; and the reason 

 probably resolves itself into a matter of accommodation, the 

 intestine of the smaller fish not being of sufficient size to 

 contain the bulk of a full-grown tapeworm. Amongst the 

 above-mentioned fish the only ones of small size are Cottus 

 scorpius and C. bubalis, which are infected with Bothrio- 

 cepAaZ«s/)u«c<o<us fairly frequently ; but the infection never 

 reaches the extent that is so commonly met with in the 

 turbot. In the smaller fish scolices are very prevalent, their 

 numbers often being counted by thousands. It is in the 

 Elasmobranchs that Cestodes come to maturity and are so 

 plentiful ; none of these are included in the present report. 



Echinorhynchs were found on only four occasions, and in 

 every case in rock-fish, namely Liparis montagui, 0/ios mus- 

 telus, O. tn'cirratus, and Gasterosteus aculeatus. 



Over thirty new records are noted in this paper, of which 

 half are in Trematodes. Records new to British waters are 

 much more numerous. 



In Part I. reference was made to the work of Olsson and 

 P. J. van Beneden on the Entozoa of North-Sea fishes. 

 Odhner's work on Arctic Trematodes* only came to hand 

 while the paper was in the press. Although not dealing 

 exclusively with the Trematode parasites of fishes, Odhner's 

 paper includes descriptions of many of the most important 

 of these, and it is to him that we owe the first exhaustive 

 accounts of such well-known species as Prosorhynchus squa- 



♦ " Die Trematoden des arktischen Gebietes," in Fauna Arctica, iv. 

 (1905) pp. 291-372. 



