During the work on southern Sakhalin (1946) and the Island of Shikotan 

 (1949) we studied the development of M. gotoi .starting from the early 

 stages of the attached larva until its attainment of maturity. Unfortu- 

 nately we did not succeed in obtaining a free-swimming larva of this 

 species because the eggs, which were isolated in special containers, 

 perished during the early stages of development. The earliest stage 

 of development of M. gotoi (Fig. 248) which was discovered on the gills 

 of Terpug,is close to the free -swimming larva of M, sebastis. The 

 general length of the body of the larvae is about 0. 3 mm and 0. 11 mm in 

 width. It is devoid of ciliary epithelium and has an elongated shape and 

 the disc is somewhat wider than the body proper. On the anterior end 

 there are 2 fully developed buccal suckers lying next to each other, 

 somewhat above the rounded pharynx. The intestine is clearly visible, 

 it is filled with partially digested food (remnants of the pigment of the 

 haemoglobin of the blood of the host), is sac -shaped, elongated (and 

 extends, nobis) up to the beginning of the disc. The pigmented eye is 

 absent although it probably exists in the free -swimming larva. The 

 attaching armature consists of 2 pairs of middle hooks and 5 pairs of 



Fig. 248. Microcotyle gotoi 

 Yamaguti, larva which has recently 

 attached to the gills of Hexo- 

 grammos octogrammus (Pal. ) 

 from the region of Yablichnoii 

 (southern Sakhalin, Sea of Japan). 



Fig. 249. Microcotyle gotoi 

 Yamaguti, middle and one edge 

 hook of the larva which recently 

 attached itself to the gills of 

 Hexagrammos octogrammus (Pal. ) 

 from the region of Yablichnoii 

 (southern Sakhalin, Sea of Japan). 



edge hooks (Fig. 249). The edge hooks have the usual shape for the genus, 

 lying in three groups: 4 hooks along the edge of the disc on each side and 

 above both pairs of the middle hooks and the rennaining 2 between the 

 middle ones near the lower edge of the disc. The 1st pair p. 



of middle hooks resembles those of M. spinicirrus Remley but, as is 

 apparent from the drawing, one of them is considerably coarser and more 



211 



229 



