EXPLANATION OF PLATE 

 PLATE 18 



Fig. 1. Wood borings ejected by Teredo, magnified 300 diameters. Observe 

 that in many of the particles the cell walls are visible. 



Fig. 2. Siphons protruding from blocks of wood containing Teredo. Photo- 

 graphed in aquarium, natural size. The long siphons are the incurrent ones. 

 The excurrent siphons are relatively short, usually protruding only two or three 

 millimeters from the openings of the burrows. Note ejected wood borings 

 around many of the openings. 



[400] 



