would "be suhmerged for only h months instead of the 8 months previously 

 employed. This change was made on November 23. 



In the control panels, Teredinidae occurred On all 58, except 

 one panel suhmerged from July 22 to August 25, 19^7. These forms were 

 mostly minute pits or emhryonic or minute specimens, hut some specimens 

 up to 10 mm in length were recorded. Infestation occurred every month, 

 so it is clearly evident that the breeding season at this location is 

 continuoiis. One panel was filled with hoth Teredinidae and Pholadidae in 

 one month, and another was filled hy Teredinidae euLone in ahout 1-1/5 months. 



Teredinidae occurred in all except one of the k^ test pajaels. 

 The maxiraum length recorded was 230 mm in one paxiel suhmerged for h months. 

 Three of these panels submerged for only k months were riddled, with 

 specimQns having maxiraum lengths of 215, 200, and I50 mm, respectively, 

 and one was well filled in a single month. The attack rated very heavy 

 eauch year. 



2. Limnoria . Limnoria showed spme evidence of activity throughout 

 the period of the test. They occurred in I8 of the 58 control panels, hut 

 no forms were recorded sufter January 28, 19^7- A maximum of 200 was 

 recorded in one of the panels suhmerged for ahout I-I/3 months, although 



U5 vas the most that occurred in the others. In the test panels, the attack 

 never rated more than a trace to low in the slight rating except in 

 the panel removed on November 23, 19^5, after 8 months' submergence, where 

 a peak rating of medium heavy was attained. 



3. Pholadidae . Pholadidae (Hiata and Martesia ) also were yery 

 active throughout the period of the test. They occurred in 27 of the 58 

 control panels, mostly ranging from pits to embryonic or minute, but up 

 to 5 nni long in one panel. In the test panels, they occurred in 59 ot 

 the i)-5, attaining lengths up to 14-0 ram in i«- months. Some of these panels 

 were almost completely filled in k months, often with Pholadidae in 

 conjuction with Teredinidae . The attack rated very heavy in 19^5 and 19^6, 

 but appeared less severe in 19^7' 



k. Sphaeroma . Sphaeroma also were present in 19^- eind 19^5, 

 occurring on a single control panel and on 6 test painels. The number on 

 any one panel was few, but from k^ to 50 foirms were recorded on a test 

 panel submei^ed for 9 months, while 75 forms were recorded on the 

 control panel infested. 



A2k.0k FouliniK Agents 



1. Silt . Silt occurred as traces to moderate deposits on all the 

 panels of both the control and test series. 



2. Algae . Green algae occurred as a trace or light growth on 

 a single panel of both the control and test series. 



115 



