Two New Trematodes of the Family Gyrodactylidae. JJ 



The nervous system is in its main arrangement similar to that 

 of Dactylogyrus. 



The testis is a dorsoventrally flattened globular organ directly 

 in front of the posterior intestinal loop and similar in its general 

 structure to that of Dactylogyrus. At its front end in the median 

 line it gives rise to a single sperm duct, which proceeds forwards 

 on the dorsal side of the ovary obliquely towards the left side and 

 from the anterior end of the ovary onwards runs for some distance 

 parallel to the intestinal ccecum close on its inner side; here the 

 duct is expanded into an elongated vesicula seminalis (fig. 11, 14). 

 It then narrows and again expands into a second smaller vesicle, 

 and at a short distance behind the anterior intestinal loop it turns 

 suddenly backwards and obliquely to the right and forms an 

 ejaculatory duct provided with muscle fibres, and finally opens at 

 the base of the chitinous penis. The latter is a hollow tube curved 

 in the form of a fishing hook, the expanded base corresponding to 

 the barb, and lies in a tubular extension of the male genital pore r 

 which lies a short distance behind the anterior intestinal loop. 

 It is of nearly uniform calibre and its base is continued forwards 

 in the form of a tongue, while its distal end has somewhat the 

 shape of the point of a Turkish sword. The supporting rod is of 

 the same general form but more curved and has numerous, small, 

 irregular cavities in its axis; its terminal end is closely apposed 

 to that of the penis, while its base is continued backwards into a 

 tongue-shaped chitinous piece united with the penis base and 

 fixed together with the latter onto an elongated fusiform mass of 

 peculiar chitinous-looking fibrous tissue (fig. 14, 15). To the 

 front end of this mass of peculiar tissue and of the base of the 

 penis is attached a muscular bundle, which runs obliquely 

 forwards and merges with the longitudinal dermal muscles; 

 another smaller bundle is attached to the base of the penis and 

 runs forwards nearly parallel to the first; a third bundle is 

 attached to the basal process of the supporting rod behind the 

 penis and also runs forwards; no doubt they are the protractors 

 of the penis. The retractor consists of two bundles inserted one 

 to the hind end of the basal mass, the other to that of the basal 



