In summertime up to the middle of August only mature para- 

 sites are encountered on both types of fishes and (then, nobis) only on older 

 fishes. Thus, M. gotoi is encountered on H. octogrammus starting fronn 

 two-year-olds (the lenirths of the fishes are from 18 centimeters) and on H. 

 lagocephalus - -among fishes with sizes from 20 centimeters (apparently 

 also two-year-olds). Mainly toward the middle of August we observe 

 Microcotyle on both fishes with a large number of eggs in the uterus which 

 are deposited simultaneously by the worms and then a new portion of eggs 

 begins to accumulate in the uterus which was just emptied. An especially 

 intensive formation and deposition of eggs of M. gotoi takes place during this 

 period. This process continues until the second half of September when 

 apparently it ceases or in any case slows down considerably. Emergence p. 119 



of larvae and the infection of fishes from the eggs deposited in the water 

 begins at the beginning of the third ten days in August in Southern Sakhalin and 

 in the first ten days of Septennber in Shikotan. Inasmuch as the larva which 

 has just emerged from the egg does not yet have clamps and since the latter 

 are incepted gradually in proportion to the growth of the larva we can, on 

 the basis of the structure of the attaching armature of the larvae, judge 

 about the periods of infection of the host, the intensity of infection and also 

 about the length of time during which it takes place. In the beginning, the 

 intensity of new infections builds quickly and then gradually decreases 

 until young stages are almost completely absent. According to the time, 

 it is apparent that in outhern Sakhalin this process is most intensive at 

 the end of August- -the beginning of September, and on Shikotan- -some- 

 what later. A strong decrease in infection takes place apparently in both 

 regions in October (on Shikotan we did not observe the end of this process). 

 Thus the emergence of larvae from the egg takes place very intensively 

 only from 15 to 20 days, although it extends generally up to a period of 

 almost one and one -half months. 



The infection of fishes takes place unequally according to ages. 

 The most strongly infected are yearlings, which until that time were conn- 

 pletely free of Microcotyle. Along with them the older stages are also in- 

 fected, although in much smaller numbers and percentages and by a smaller 

 number of parasites. In this case, a great role is played by the location 

 of the fishes of different ages. Thus, fishes up to 20 centimeters in length, 

 i.e., until the age of two, keep much closer to the shore all the time, 

 whereas the older ones are encountered in shallow places in much smaller 

 numbers and apparently rarely after spawning. After the infection of the 

 fish, the worms grow rather slowly so that at the most after ten days they 

 have 10 to 15 clamps instead of the 38 to 42 pairs characteristic of adults. 

 Apparently the full development of the attaching apparatus is delayed until 

 the late fall and the worms reach nnaturity towards the spring -fall of the 

 following year. The data obtained fully correspond to the sketchy infor- 

 mation about the biology of the Terpug (Rock, Trout, or Starling, nobis). 

 It is known that the latter does not reach maturity before the age of two 

 years. The adults usually maintain themselves at depths of more than 10 



124 



