through December. There were specimens in all except 5 of the ^0 test 

 panels, some panels Tsecoming riddled in the short period of 6 months. All 

 except 2 of the 9 consecutiYe panels submerged from 6 to 8 months up to 

 October IS, 19^5^ were riddled, and one of these panels was well filled. 

 A maxlmiaa length of 56O mm was recorded in a panel sulamerged for 8 months. 

 Ihe attack rated very heavy in 19^5 and appeared to be eq u ally heavy 

 in 19^6 and 19^7, although the period of sulmergence had "been reduced from 

 6 to Ij- months. 



2. Limnoria . Limnoria were eictive throughout the period of the 

 test but never occurred in parti culeirly destructive numbers. They occurred 

 in 21 of the 58 control panels, but there were never more than 125 in 

 any single panel, and no forms occurred until after March 18, 19^5. In 

 the test panels, they occurred in all except 2 of the 59> "but the attack 

 never exceeded a low slight rating in any one year. 



A55,0I^ FoxLling Agents 



1. Silt'. Silt occurred on 55 of the 58 control panels and on 

 all except one of the same number of test panels. In the control 

 panels, the deposits ranged from traces to occasionally light, while 

 on the test panels they ranged from traces to mostly light, and moderate 

 on one panel. 



2« Algae. A trace of green algae occurred on e. single test panel. 



5. Invertebrate animal phyla . 



a. Coelenterata (hydroids and Metridium ) . Hydroids occurred 

 on 8 of the 58 control peinels emd on 28 of the same number of test 

 panels. They: rated as traces on the control panels emd from traces to 

 occasionally light growths on the test panels. A solitary specimen 



of Metridlum» a member of a different group of Coelenterata , occurred 

 on a single test panel. 



b. Bryozoa (encrusting and filamentous ). Encrusting Bryozoa 

 were lacking on the control panels and occurred rather sparingly on 



11 of the 59 test pajiels. Cal 1 ipora craticula , Cheiloporina praelonga , 

 Cryptosu la sp., Dendrobeania lichenoides , and ELectra sp. were identified. 

 Filamentoxis Bryozoa were lacking on the control panels but occurred 

 more or less abimdantly on 25 of the 59 test panels. Bugula - pacifica , 

 B. f labellata , and B. sp. were the only ones identified. 



c. Annelida (annelid worms ). Serpvilid ( Serpula ) tubes like- 

 wise were lacking on the control panels, but they occurred on 10 of the 59 

 test panels, the largest number being 50 on any one panel. 



d. Arthropoda (crustaceans ). Bft3.anus (beoTaacles) occurred on 



156 



