diameter recorded was 12 una and 11 mm cm the coatrol panels of Test Boards 

 1 ff ,n fl 2, respectively, and 2^ mm In 9 manths and 23 ma. in k months on the 

 test panels of Test, Boards 1 and 2, respectiTely. One control panel was 

 505^ covered; 7 test panels on Test Board' No. 1 were from 5<^ to 80f> 

 covered after 8 months' submergence, while 12 panels on Test Board No, 2 

 were from 5056 to IOO5& covered, some after only k months' submergence. 

 A]i5)hipods ( Corophima ) occurred on a single control panel and on 5 of the 

 test panels of Test Board No. 1, while on Test Board No. 2, they occurred 

 on only 2 of the test panels. A ranxJTmim of lK)0 were recorded on a single 

 test panel of the first hoard. 



e. Moll;isca (nonhorlng mollusks ). Miscellaneous mollusks 

 occurred occasionally on the panels of both test hoards. A few specimens 

 of Mytilus (mussels) occurred on 3 of the test panels of Test Board No. 1, 

 and on only one test panel of Test Board No. 2. A few specimens of Anomia 

 (jingle- shells) were recorded on a single control panel and on 6 test 

 panels of Test Board No. 2. A few specinens of Ostrea (oysters) occuixed 

 on 2 test panels of Test Board No. 1,' and on 5 test panels of Test Board 

 No. 2. A maximum diameter of 77 inm was recorded after h months' sub- 

 mergence, 



f. Chordata (tunicates ). Tunlcates occurred more or lees 

 abundantly on k control panels and on 6 test panels of Test Board No, 1, 

 also on 10 control panels and on 27 test panels of Test Board No, 2, 

 Botryllus schlosserl was the most numerous of these, tunlcates, "but 

 Molgula and ascidians also were identified. 



Al4. 05 SuTTmwry and Conclusions 



1. Installation . Test hoards of -fche panel type, installed 



June 16, 19hk, at the Norfolk Naval Shipyard at Portsmouth, Virginia, and 

 July 5, 19kh, at the U. S. Naval Operating Base at Norfolk, Virginia, are 

 still "being operated. The results of these tests have "been suTtmwrized to 

 the end of 19^7. 



2. Test Eesults . 



a. Borers . The activity of the Teredinidae differed 

 markedly at the two locations. At the Norfolk Naval Shipyard at Portsmouth 

 the attack attained peak ratings of moderate in 19M^ and 19^5* "but rated 

 only slight in 1946 and 19^7 . At the U. S. Naval Operating Base at 

 Portsmouth, however, the attack rated very heavy each year. No evidence 

 of Limnoria was recorded at the Norfolk Naval Shipyard at Portsmouth, and . 

 the attack at the U. S. Naval Operating Base at Norfolk rated only a trace 

 in IS^A- and 19*^6; no Limnoria appeared in l^kO and 19^7. 



68 



