MANN: CONADAI, DKVKI.OI'MKNT IN ARCTIC A ISLANDICA 



*m 









""># **i. S ft* 



- * SEr^ Vie 



Figure 4.— Midventral sections of hermaphrodite Arctica inland ica collected at Station A, 2January 1980. A. Section illustrating 

 spatially separate male (B) and female (C) gonadal tissue. Scale bar 1 mm. B. Expanded view of male gonadal tissue illustrating 

 spent male follicle. Scale bar 50 n. C. Expanded view of female gonadal tissue illustrating degenerating ova. Scale bar 50 p. 



ing during one annual cycle in either of the two 

 years when observations were made. Gonadal 

 maturation, then, probably occurs only once per 

 year in each individual clam. The mean diameter 

 of the ova taken from histological sections of ripe 



female clams was 52.4 /x (n = 59 ova). This com- 

 pares with a value of 66.3 /i ( n = 22 ova) obtained 

 from unfertilized eggs stripped from ripe, live 

 animals. The disparity between preserved and 

 live material in the present instance is probably 



319 



