Biological Station in August 1950, U. A. Strelkov obtained the free- 

 swinruning larvae. The larvae (Fig. 242) emerge from the eggs 4 days 



Fig. 242. Microcotyle pomatomi 

 Goto, free-swimming larva. 



Fig. 243. Microcotyle pomatomi. 

 Goto, attaching arnnature of the 

 free -swimming larva. 



after deposition of the egg. They have an elongated torpedo -shaped 

 form, 0. 2 mm in length and 0. 06 nnm in width. The ciliary covering is 

 located in three zones just as in M. spinicirrus. The distribution of the 

 zones is the same: the last, somewhat more powerful zone lies on a cone- 

 shaped growth and is divided by its tip into two halves. It has a well- 

 developed pigmented eye. One specimen at our disposal had two eyes developed 

 to absolutely the same degree; nowhere have we ever observed such a 

 monstrosity. The entire structure of the larva cannot be determined 

 from the preparations. The attaching disc is fairly well-delineated from 

 the body, it bears 5 pairs of edge and 2 pairs of middle hooks (Fig. 243). 

 The edge hooks are distributed just as among the preceding types, i.e. , 

 one pair between the middle hooks and the rest somewhat higher along 

 the sides of the disc. The 1st pair of the middle hooks is of the same 

 shape as among M. mugilis,but is somewhat nnore massive. Even though 

 it does resemble that of M. spinicirrus Remley in type or M. mugilis Vogt 

 the 2nd pair is, nevertheless, considerably different. The hooks of this 

 pair resemble the middle hooks of the lowest monogenetic trematodes. 

 They have a basic part elongated arid widened in the middle, they have 

 strongly curved powerful point and small offshoots --extensions, standing 

 at almost right angles to each other. The length of the edge hooks is 

 about 0. 012 mm, the length of the 1st pair of middle hooks is 0. 042 mm 

 and of the 2nd pair--0. 026 mm. In the material collected by U. S. Strelkov 

 there are no stages of development subsequent to the larva. 



p. 208 



226 



