300 



contained shipworms which were producing free-swininiing larvae; it is probable, 

 although not certain, that he was dealing with this species. In Pearl Harbor Teredo 

 parksi appears to mature more slowly and to reach a larger size, the diflference doubt- 

 less being due to temperature conditions. 



In Samoa Teredo parksi appears to breed uninterruptedly throughout the year, 

 but in Hawaii the breeding activity, as indicated by settlement of larvae, reaches a 

 maximum in August, September and October, progressively decreases from November 

 to March, and reaches a minimum, possibly ceasing altogether, in April. 



Teredo bartsehi, described by Clapp (1923) from Port Tampa, Florida, was found 

 in the test blocks sent in from Nawiliwili, occurring most numerously in the blocks 

 placed after September, and somewhat sporadically in the earlier blocks. 



This species occurs rarely in San Diego Bay, not more than a half dozen speci- 

 mens having come to light in two years' investigation. It seems likely that the organism 

 has been introduced in shipping from the islands, or from Atlantic waters, and either 

 has not foimd the new environment fa^•orable, or has not had sufficient time to become 

 established. The status of Teredo bartsehi in San Diego Bay appears accordingly to 

 be similar to that of Teredo diegensis in San Francisco Bay. 



Of the biology of Teredo affinis. Teredo furcillatus, Teredo sanwaensis and Teredo 

 trtilliformis, little is known except the partial distribution, as given in Chapter 2. 

 The list of localities for these forms will uncjuestionably be extended with increasing 

 knowledge of the fauna of the islands. 



The test board at Nawiliwili was placed February 1, 1923. In the earlier blocks 

 Teredo affinis predominates, and is very destructive; but in the blocks placed after 

 September it is almost entirely replaced by Teredo bartsehi and Teredo diegensis. A 

 few specimens of T. aff>nis have been found in the blocks from Honolulu Harbor. 



Teredo furcillatus has occurred in limited numbers in the blocks from Tutuila and 

 Honolulu Harbor. The longest burrow recorded measured 6.7 cm. The species does 

 not appear to be of much economic importance. 



Teredo sanwaensis has been found onl\- in Samoan waters, where it occurred 

 commonly in the blocks from a test board placed in November, 1923. This board 

 was lost before adequate data were secured, and a second board placed the following 

 June was not at all attacked by this species. 



Teredo trulliformis occurred commonly in the blocks from Honolulu Harfxir, and 

 somewhat rarely in the blocks from Pearl Harbor and Nawiliwili. The longest burrow 

 recorded measured 9 cm. 



