of the 18 control panels received and on 11 of the 25 test panels. 

 The maxlraraa length was 10 mm on the control pcaiels and 20 mm on the 

 test panels. The maximum numher on any of these test panels van 20. 



f. Arthropoda (crustaceans ). Balanus (barnacles) occurred 

 fairly frequently on the panels of Test Board No. 1 "but only sporadically 

 on the* panels of Test Board No. 2. On Test Board No. 1, they occurred 

 on 27 of the 43 control panels and on 27 of the 50 test panels. The 

 maximum diameter recorded was 18 mm on the control panels and k2 mm on 

 the test panels after h months' submergence. Eight control panels eind 



5 test panels were from 50^ to 805^ covered. On Test Board No. 2, 

 barnacles occurred on 5 of the 18 control peuiels received and on k of 

 the 25 test panels. The maximum diameter recorded was 8 mm on the control 

 pemelB and 12 mm on the test panels. 



g. Mollusca (nonboring mollusks ). Miscellaneous molluslcs 

 occurred sporadically on the panels of both test boards. Anomia (jingle- 

 shells) occurred on 5 of the k'^ control painels and on 15 of the 50 test 

 panels in Test Board No. 1; while in Test Board No. 2, they occurred on 



k each of the control and test peinels. Maximum diameters of 8 mm were 

 recorded on the control pan&ls and of 15 inm on the test panels. The 

 TTiftTlminn number on a test panel was 40. Traces of Ostrea (oysters) 

 occurred on a single control panel and on 12 test panels of Test Board 

 No. 1 and on five test panels of Test Board No. 2. A trace of Yermetidae 

 occurred on a single test panel of each test board. 



h. Ohordata (tunicates ). A few colonies of txuiicates 

 occurred on occasional panels of both test boards. They occurred on 

 3 control panels and on 5 test panels of Test Board No. 1 and on 

 2 control panels and a single test panel of Test Board No. 2. Botryllus 

 schlosseri was the only one identified. 



A46.05 Summary and Conclusions 



1. Installation . Of the 2 test boards of the panel type 

 installed at the U. S. Submarine Base at Balboa, Canal Zone, on June 

 15, 19hk, one is still being operated, and the other was discontinued in 

 November 1945* The results of these tests have been summarized to the 

 end of 19^7. 



2. Test Beaults . 



a. Borers . Teredinidae were active every month of the 

 year, showing that the breeding season is continuous at this location. 

 The attack was very heavy on both test boards, with panels becoming 

 filled, or occasionally riddled, even after the period of submergence 

 Was reduced from 8 to 4 months. Ljmnoria were present throiighout 



217 



