S. sqiiatinae to the genus Megalocotyle ^ although she did not make corres- 

 ponding conclusions from this. 



Its occurrence on sharks can also serve as indirect substantiation of 

 the independence of this genus, whereas all the representatives of Megalocotyle p. 378 



(s . str. ) parasitize Perciformes (see page 258). 



The structure of the disc in Macrophyllida is interesting and 

 enables us to clarify the appearance of forms without septa. In this odd 

 worm the two posterior septa, in which the middle hooks are located, ^ do 



1 



Johnston points to the presence of two pairs of the latter; this is hardly 

 correct; it is more likely than not that he did not notice the third smallest 

 pair as well as all the edge hooks. 



not contain any musculature and are clearly reduced. Johnston writes^ in 

 his important work (Johnston, 1930a) that the disc of M. antarctica Hughes 

 has 5 peripheral depressions and that its "posterior depression is large and 

 is bisected by two atrophied rays deprived of special musculature. " These 

 "rays" represent the disappearing posterior septa of the rest of Megalocotyle 

 which is substantiated by the presence of middle hooks in them. Thus, 

 Mac rophyllida demonstrates one of the possible ways of the disappearance 

 of septa and a very odd one because among a majority of Capsalidae it is 

 precisely these septa which are more powerfully developed and apparently 

 are preserved longer than anything else. 



3. Subfamily Trochopodinae (Price, 1936) Sproston 1946 



(Figs. 28, 98, 102, 113, C, 196-202, 278, B, 280) 



Benedeniinae Johnston, 1931, part. 



Capsalidae .having the attaching disc with a central, often 

 weakly expressed depression and an even number (6 - 12) of peripheral 

 ones delimited from each other by muscular septa and sometimes weakly 

 developed septa or septa deprived of musculature. The middle hooks number 3 

 pairs. The anterior end has a weakly developed cephalic lobe and 2 

 strongly developed suckers. The rest (of the characters are, nobis) just 

 as among Megalocotylinae. 



Parasites of marine fishes, basically Perciformes, but are 

 encountered also on a number of other orders. 





451 



