Record of the pH reaction of the water, tased on readings 

 made at various times each month, showing the general range 

 throughout the yeeir at each location 



A40.05 Marine Borers 



1. Teredinidae . Teredinidae . including Teredo navalis and T. 

 ( Lyrodus ) sp., were active at all three locations throughout the period 

 covered by the tests. The detailed figures on their occurrence at each 

 of these locations are summarized below. 



a. Shipbuilding Ways No. 8 . Teredinidae occurred in 9 of 

 the 57 control panels. They ranged from minute pits ajid embryonic 

 specimens to those specimens up to 20 mm in length. The breeding season 

 at this location appesLred to extend from the middle of May through 

 October. In the test panelB> Teredinidae occurred in 29 of the 58, with 

 a maximum length recorded in one panel submerged foi* 8 months. Two of 

 these panels were filled after having been submerged for 8 eind 9 months, 

 respectively. The attack at this location rated very heavy in 19^5^ 

 moderate in 19^6, and very heavy in 19^7. 



178 



