e. MolluBca (noriborlng molluBke ). A single specimen of 

 enjbryonlc ^ytllus (massels) vaa recorded on one of the control panels. 

 MuBselB occurred on 15 of the 50 test panels, the majclmum nuniber on any 

 one panel "being 50 • Lengths up to 8 and 9 mn were recorded on panels 

 submerged for 3 and 5 months, respectively, vhlle the maximum length 

 recorded vas l8 mm on a panel that had Inadvertently "been left sub- 

 merged for ik months, A few specimens of Anomia (jingle-shells) were 

 recorded on 6 of the test panels, and a few specimens of Saxi cava were 

 recorded on one other panel. 



f. Chordata (tunicates ). Tunicates occurred on h of the 50 

 control panels and on 15 of the 50 test panels. The greatest number of 

 colonies recoisied on any panel was 150. Botryllus achlosserl t Molgula , 

 and Clona were each identified a number of times. 



A5.O5 Simrnw-ry and Conclusions 



1. Installation . A test "board of the panel type was operated at 

 the U. S. Naval Station at Portland, Maine, from June 2, 19^^^ until its 

 discontinuance on March 27, 19^7* to detennine the identity and prevalence 

 of marine "borers and fouling organisms at this location. 



2. Test EesultB , 



a. Borers . There was no evidence \diatever of the activity of 

 Teredlnidae during the nearly 5-year period covered "by this test. Limnoria , 

 however, were active in the test panels throughout the period of the test, 

 attaining a peak rating of moderately heavy at the end of 19^5 and again 

 in 19h6, 



"b. Fouling Organisms . Silt and invertebrate animals "belonging 

 to six phyla contrl"buted to fouling of the panels. The latter conprised 

 hydroids, encrusting and filamentous Bryozoa, annelid worms, "barnacles 

 and an?)hipods, mussels emd J ingle -shells, and tunicates. Of these or- 

 ganisms, hydroids occurred with by far the greatest frequency, "barnacles 

 and mussels occurred with less frequency, encrusting Bryozoa occurred 

 with still less frequency, while the occurrence of the other organisms 

 was purely sporadic or occasional. 



55 



