Figure 6: Early larval development in Mactra chinensis (from Medvedeva and 



Malakhov, 1983). 

 A — larva with everted shell gland and blastopore, lateral view; B — trochophore; 



C — commencement of shell formation, 

 abo — aboral organ; ar — archenteron; mt — mesodermal teloblasts; r — rudiment of shell; 



sg — shell gland. 



