96 



Figure 61 (contd.). 



lateral teeth resemble tubercles on both sides of the hinge. The right valve has 

 two indentations corresponding to the primary plates of the left valve. The 

 ligament is triangular and posterior. 



Ecology 



In Peter the Great Bay, larvae of Spisula sachalinensis appear at the end 

 of June and are most numerous in mid- July. Larvae settle in shallow water, 

 sandy inlets, well-warmed by the sun. Freshening of water adversely affects 

 the young of the year population (Tabunkov, 1971). 



Hayashi and Terai (1964) have described external changes in the pediveliger 

 after settling. Medvedeva (1981) gives a brief description of changes in the 

 hinge during larval growth. Some information is also available on rearing 

 larvae of S. sachalinensis in the work of Imai and coworkers (1950). 



