B. mexicana , B. ( NauBltora ) ep., were extremely active each year in the 

 panels of "both test 'boards. They occvirred in all except 2 of the hh 

 control panels of Test Beard No. 1 and in all except one of the l8 that 

 were received from Test Board No. 2. The uncontaminated panel was the 

 last one removed after 5 days* submergence. Most of the specimens in 

 these peinels were embryonic or minute, but some specimens up to 52 mm 

 emd 40 mm in leiJgth were recorded in Test Boards No. 1 and No. 2, 

 respectively. Teredinidae were found infesting the control panel every 

 month of the year, thus showing that the breeding season at this location, 

 is continuous. Infestation and development in these panels were lowest, 

 however, from the middle of February to the middle of April. 



Teredinidae occurred in all the test panels of Test Board No. 1 

 except in a panel that was removed in November 19^5/ after having been 

 submerged for only 5 days, and in all of Test Board No. 2 except the 

 first and last, the latter of which was removed after having been sub- 

 merged for only 5 days. In both test boards, the majority of the test 

 panels were either filled or riddled by JTeredinidae . In Test Board 

 No. 1, they continued to be generally filled, or oocasioneilly riddled, 

 even after the period of submergence was reduced from 8 to 4 months. 

 The maximum length of specimens recorded was 250 mm in Test Board No. 1 

 and 290 mm in Test Board No. 2. The attack by Teredinidae at this location 

 is rated very heavy. 



2. Limnoria . Limnoria also occurred in both test boards 

 throughout the period of operation. They occurred as mere traces in 50 

 of the hk control panels received from Test Board No. 1, and in 6 of 

 the 18 control panels in Test Board No. 2. They also occurred, mostly as 

 traces, in kk of the 51 test panels received from Test Board No. 1 

 and in 20 of the 25 in Test Board No. 2. In Test Board No. 1, the 

 maximum attacks attained ratings of slight in 1946 and 1914-7; while in 

 Test Board No. 2, only mere traces were recorded. 



5. Pholadidae . Pholadidae , including Martesia and Hiata, 

 also occurred at this location. In Test Board No. 1, juvenile speci- 

 mens were recorded in only 2 control panels and from 1 to 20 specimens 

 occurred irregularly on 18 of the 51 test panels, the maximum length 

 being 28 mm. In Test Board No. 2, Juvenile specimens were recorded on 

 only 2 control panels and from 1 to 6 specimens occurred irregularly 

 on 7 of the 25 test panels, the length not being recorded. The Pholad 

 attack thus rates as slight in Test Board No. 1 and practically only 

 a trace in Test Board No. 2. 



Aii-6.0l4- Foulina Agents 



1. Silt . Silt occurred on all the panels of both the control 

 and test series on both test boards. On Test Board No. 1, the deposits 



215 



