CHAPTER III 



OCCURRENCE OF THE GENERA OF MONOGENETIC 

 TREMATODES ON FAlvOUES AND ORDERS 

 OF THEIR HOSTS --FISHES 



There is no doubt that the materials presented above demand p. 249 

 further examination; however, before passing to it we nnust turn our 

 attention to the following group of facts, namely- -to the nature of oc- 

 currence of the genera of Monogenoidea on the families of fishes. Just 

 as in the preceding presentation which was dedicated to the discussion of the summary 

 Table 4, we shall utilize the materials on the same 958 species and ex- 

 amine the data obtained one by one starting from the genera encountered 

 only on one family of fishes. In the first place, in the discussion about 

 occurrence we will have to utilize the corrections which were made earlier, 

 and in the second place conduct a certain verification of the initial materials 

 which demand significant changes in a number of cases as will be seen later. 

 Speaking about utilization of the previous data we mean that in the text and 

 tables that will follow, faulty or doubtful data which have already been 

 analyzed before will not be included; specifically, that for a number of 

 genera the data about the finding on separate families of hosts will be 

 excluded: Amphibdella [A. maccallumi (Johnson and Tiegs) ] on Squalidae; 

 Bilaterocotyle [B. chirocentrosus (Chauhan)] on Chirocentridae; Cyclocotyla 

 (C. bellones Otto) on Sparidae and Maenidae; Dactylogyrus (D. inversus Goto 

 and Kikuchi) on Scombridae; Diclidophora [ D. palmata (Leuckart) ] on 

 Bothidae; Calicotyle (C. kroyeri Diesing) on Bothidae; Encotyllabe (E. 

 nordmanni Diesing and E. pagrosomi MacCallum) on Pomacentridae and 

 Latilidae; Heterocotyle H. minima (MacCallum) ] on Squalidae; 

 Megalocotyle FM, zschokkei (Mola)] on Cottidae; Squamodiscus (S. belengeri 

 Chauhan) on Muraenidae; Tetrancistrum (T. sigani Goto and Kikuchi) on 

 Serranidae; Trochopus (Tr. brauni Mola) on Cottidae; and, Urocleidus (U. 

 mimus Mueller) on Esocidae. In addition, during the tabulation of the 

 number of species parasitizing a given family the indications for Gyro- 

 dactylus on the presence of G. medius Kathariner on Cobitidae and for 

 Diplectanum on D. aequans (Wagener) from Sciaenidae will be excluded. 

 Further, for Ancyrocephalus--(A. alatus Chauhan) information about the 

 finding on Ariidae, Mugilidae, and Scopelidae and for Diplectanotrema 

 [ D. balistes (MacCallum)] all the data about the families of hosts are given 

 with a question nnark even though they are preserved in the tables. 

 Finally, in addition to those indicated for Benedenia [ B. melleni (MacCallum)] 

 information about the findings only in natural conditions will be included 

 in the table. 



Among the 154 known genera of monogenetic trematodes of 

 fishes, 95, i.e., almost two-thirds, are encountered each only on one 

 family of fishes. Of these genera, 67 contain only one known species at p, 250 



280 



