During the time of his work at the Sebastopol Biological 

 Station, U. A. Strelkov (Strelkov, 195 3) hatched a free -swimming larva 

 of Axine belones Abildgaard from the gills of Belone belone euxini (Gunther). 

 In addition to that, during the 2Znd cruise of the expeditionary vessel 

 "Vityaz" in 1955 we obtained the development of two as yet undetermined 

 species of Axine from the gills of flying fishes (Exocoetidae), which are 

 conditionally designated by us as Axine sp. I and Axine sp. II. In the 

 article of U. A. Strelkov the following description of the larva of A. 

 belones Abildgaard is given: "The body of the larva is elongated, it is 

 widened toward the posterior end where the attaching disc is located 

 (Fig. 257 --B. B. ). The length of the body is 0. 2 - 0. 3 mm. The width 

 is 0. 5 - 0. 8 mm. One double, pigmented eye is located in the anterior 

 end. On the body of the latter one can clearly distinguish three zones of 

 cilia. The first zone is located on the anterior end, the second in the 

 middle part, the third on the posterior end of the body. The anterior 

 ciliary zone is somewhat wider than the other two and reaches approxi- 

 mately the level of the eye. The second zone is somewhat narrower than P* ■^^^ 

 the first, and the third zone, lying on the posterior end of the attaching 



0.0 tMH 



Fig. 259. Axine sp, I, free- 

 swimming larva. 



Fig. 260. Axine sp. II, free- 

 swimming larva. 



disc, is narrower than the two preceding zones. The attaching disc 

 occupies about 1/3 of the body and bears 7 pairs of hooks of which 2 pairs 

 are large middle hooks and 5 pairs are small lateral hooks (Fig. 258, B). 

 The larger middle hooks are located along both sides of the mesial line of 

 the body and have a different structure. The first pair resembles the 

 middle hooks of Dactylogyrus in shape but with a larger handle. The length 

 of the hook is 0. 032 - 0. 034 mm; the length of the point is 0. 009 - 0. 01 mm, 

 the length of the handle is 0. 012 - 0. 014 mm, the second pair of hooks 

 somewhat resembles the small edge hooks but is much larger. They have 

 a thin, long straight handle and point. The average length is 0. 035 - 

 0. 044 mm, the length of the point is 0, 008 -.0. Oil mm. In the living 



234 



