described.because Guiart (Guiart, 1938) cites this name but does not give 



any description; apparently he establishes this species on the basis of the 



drawing from the textbook of Fuhrmann (Fuhrmann, 1928, Fig. 1) on which 



there is an indication that this parasite is from Raja sp. The data concerning 



the finding on Sphyrnidae are based on the fact that one sample of the 



comnnon parasite of Xiphias gladius --Tr. coccineum --is in the collection 



of the Washington National Museum from the collection of MacCallum (see 



Price, 1939) with the indication that it was found on the gills of Sphyrna 



zygaena (L. ). Finally, in the index to the literature on Medical and 



Veterinary Zoology there is an indication of the presence of Tr. papillosum 



on Carcharias glaucas (L. ), which has never been confirmed by anyone p. 262 



(Stiles and Hassall, 1908). Until fresh contemporary data on the finding 



of representatives of Tristoma on families other than Scombroidei are 



obtained, one must consider that the genus Tristonaa is characteristic only 



for the latter. 



As regards five genera of Monogenoidea indicated in Table 12^ 

 we arrive at the following conclusions. 



1. Two genera Calicotyle and Capsala are encountered on seven 

 families of fishes; the first on Selachii and Holocephali, i.e., on two 

 classes of fishes; and the second on two groups of related families and 

 these groups are not related to each other (Scombroidei + Tetrodontiformes). 



2. On six related families of fishes, one genus, Squalonchocotyle, 

 is encountered and predominantly on sharks (only one species on skates). 



3. One genus of Monogenoidea--Tristoma--i3 encountered on 

 three fanailies of fishes related to each other. 



4. The genus Urocleidus should be considered basically 

 characteristic for Centrarchidae but should be excluded from further 

 discussion as artificial. 



According to the literary data, Choricotyle and Encotyllabe 

 parasitize nine families of fishes (Table 14). For Choricotyle there is 

 another indication on one species--Ch. pinguis described by Linton (Linton, 

 1940) from Albatrossia pectoralis (Macruridae) but actually it is a repre- 

 sentative of the genus Diclidophoropsis, to which this species is attributed 

 by us. The data concerning the occurrence of Choricotyle show that this 

 genus was discovered on seven families of the superfamily Percoidae and 

 on 1 other family of Perciformes--Trigilidae, which is rather remote 

 from Percoidae. The information concerning the finding of Choricotyle 

 on Clupeiformes are apparently erroneous. These data belong to the often 

 aforementioned Chauhan (Chauhan, 1945) who found two individuals of 

 Cyclocotyle (=Choricotyle), multaetesticulae Chauhan on the gills of Pellona sp. 

 It is possible that there is here an erroneous indication (determination?) of 

 the host. 



297 



