Discocotylidae are discovered on Clupeiformes and Cyprini- p. 274 



formes. Among the Clupeiformes the Discocotyle are encountered on 

 Salmonidae and Thymallidae, the close relations of which have already 

 been discussed (page 230 ). Among Cypriniform.es, this family is discovered 

 on Cyprinidae (6 species of two genera), Catostomidae (1 species) and 

 Cobitidae (1-0 species). All three families are closely related (pages 230 - 

 256). The relations between Clupeiformes and Cypriniformes are not clear, 

 so that it is impossible for the time being to say whether or not they are 

 linked genetically (Suvorov, 1948). 



Gastrocotylidae are encountered on eight families of Perciformes^ 

 Of these families six (Carangidae, Coryphaenidae, Scombridae, Cybiidae, 

 Bramidae and Thunnidae),on which were discovered 23 species of six genera, 

 belong to the group of Scombroidei according to Gregory. One genus of 

 Gastrocotylidae is encountered on Serranidae and another cne on Sparidae. 



I 



The last species in addition to that was also discovered on Sconnbridae. 



The last two families are somewhat further removed from the first. The only 

 species discovered on the Mugiliformes is Chauhanea madrasensis 

 Ramalingam from the gills of Sphyraenidae. The Perciformes and Mugili- 

 formes are in rather close relation (Suvorov, 1948). 



Mazocraeidae are encountered almost in the equal numbers of 

 species on Clupeiformes and Perciformes. In origin the Perciformes un- 

 doubtedly are linked with the old (phylogenetically older, nobis) Clupei- 

 formes (Suvorov, 1948). Among the Clupeiformes the Mazocraeidae are 

 known only on Clupeidae, and on four families: Scombridae (5 species of 

 three genera), Thunnidae (1 species), Bramidae (1 species, see page 259 ) 

 and Sciaenidae (1 species, see page 259) from the Perciformes. The first 

 three families undoubtedly are closely related and belong to Scombroidei 

 in the understanding of Gregory, as has already been indicated. 



Monocotylidae are encountered on skates --Trigonidae (7 species 

 of worms), Rajidae ( 9-8 species), Myliobatidae (2 species), and Rhinobatidae 

 (3 species); on sharks --Carcharhinidae (2 species), Lamnidae (1-0 species), 

 Sphyrnidae (2-1 species), Pristiophoridae (1 species), and Squatinidae (1 

 species), and also on Chimaeriformes (Chimaeridae --Calicotyle affinis T. 

 Scott, see page 228 ). As we have already indicated earlier, the inter- 

 relations between the sharks and skates are sufficiently close. As for the 

 Chinnaeriformes, their relations with Selachiiformes are stated on page 300 . 

 At any rate these two orders are much closer to each other than each of 

 them is to the rest of the contemporary fishes :in spite of the fact that they 

 separated at least in the Devonian. The presence of C. affinis on both at 

 the same time corresponds fully with this, and, so to speak, underlies their 

 consanguinous ties. 



313 



