10 Trans. Acad. Sct. of St. Louis 
a test-block submerged June Ist and removed August 
14th, contained Teredo johnsoni with 30 mm. tubes. At 
San Juan, Porto Rico, a test-block placed October 1, 
1922, contained 30 mm. Teredo johnsoni on January 2, 
1923, and wood placed in the water July 1, 1923, con- 
tained small specimens on August 1, 1923. At Fajardo, 
Porto Rico, wood submerged from January 9 till April 
30, 1923, contained several specimens of this species. At 
St. Thomas, Virgin Islands, wood submerged four 
months and removed January 1, 1923, contained sev- 
eral specimens. 
