sharpened in the lower part, and which have a length (along the curve) of 

 about 0. 040 mm. There are no traces of the connecting plate of the second 

 pair. The eye spots are of the usual form and location. The digestive 

 system has a rounded pharynx, 0. 02 mm in diameter, and circular in- 

 testine without traces of the posterior blind growth characteristic of the 

 A. siluri. There aren't any traces as yet of the sex armature. 



Subsequent development has not been followed through, but 

 its progress is evident. 



All in all, one can note that the development of representatives 

 of Ancyclodiscoides is close to that of Ancyrocephalus which has larvae 

 with the inceptions of middle hooks and differs sharply from the develop- 

 ment of Protancyrocephalus among which the process of formation of the 

 middle hooks proceeds simultaneously. 



7. The development of Bychowskyella Achmerow 



The genus Bychowskyella, described in 1952 from Amur 

 Bagridae by A. H. Achmerow, resenables Ancylodiscoides in its structure, 

 but is easily distinguished by its peculiar armature of the attaching disc 

 (Fig. 175). The latter carries two pairs of middle hooks of different size, 



Fig. 175. Bychowskyella pseudobagri 

 Achmerow, attaching armature of an 

 adult worm from the gills of Pseudo— 

 bagrus fulvidraco (Rich. ) from the 

 Island of Hanka. 



Fig. 176. Bychowskyella pseudo — 

 bagri Achmerow, free-swimming 

 larva. 



175 



