Table 2. — Results of "t" test comparing measurements of Raritan Bay hard 

 clams. Mercenarla mercenaria, collected in 1974 and 1975. 



Highly significant (P < 0.01). 



average were smaller at each age than those at 

 New Dorp Beach (Fig. 2). 



mining five stages of gonadal condition, as fol- 

 lows: 



Reproductive Cycle 



This part of the study focused on a microscopic 

 examination of the cellular events leading up to 

 an accumulation of sex cells in the gonads and 

 their disappearance during the spawning act. Pe- 

 riodic sampling identified the time and duration 

 of spawning. Cellular structures within the sex 

 cells and alveoli walls were important in deter- 



Fentales 



Early stage. Alveoli semicontracted, base- 

 ment membrane thickened, and small oocytes 

 embedded in the alveoli walls. 



Late stage. Oocytes more numerous at the 

 basement membrane, some of larger diameter ex- 

 tended into the lumina of alveoli, but attached to 



120 



. WARD POINT 



100 



E 



e 

 eo 



z 



60 



X 

 40 



20 



. NEW DORP BEACH 



t 



\*' 



* 



-I I I I l_ 



4 6 8 

 AGE 



10 12 14 



10 12 

 AGE 



16 



18 20 



Figure 2. — Mean, standard deviation, and range of shell lengths (mm) vs. age (yr) relationships of hard 

 clams, Mercenaria mercenaria , at Ward Point and New Dorp Beach, Raritan Bay, 1974-75. 



656 



