JAPANESE PAEOLO, CERATÜCEPHALE OSA WAT, N. SP. O 



of Owari, from Shimizu Harbor in Suruga, from Ito in Izu, and 

 from Matsushima and Hachinohé on the east coast of Northern 

 Japan. 



With these remarks I proceed to record the fuller details 

 of my observations in the following order : 1) on the immature 

 phase, 12) on the mature phase and 3) on the breeding-swarm. 



1. Observations on the Immature Phase. 



Habitai. — The immature worms or the atoca of the species 

 (PI. I., fig. 1) occur in great abundance between the tide marks 

 along the Sumida River, on which Tokyo is situated, for a 

 distance of about six miles from its mouth, and also in the 

 adjoining parts of the Gulf of Tokyo. They also extend some 

 distance into the tributaries, canals and ditches, which empty 

 into the waters just mentioned. 



At the ebb-tide they are found burrowing in the mud or 

 sand to a depth of a foot or more. The entrance of the burrow 

 is usually indicated by a small round hole on the surface, the 

 margin of which is always slightly raised above the level. With 

 the flood-tide, irrespective of the hour of the day, they leave 

 their retirement and creep about on the bottom. They are then 

 very active and voracious, feeding on various aquatic animals and 

 plants. Often they are seen to dip with the head end into the 

 bottom mud or sand in search of food. 



Size and (/encrai shape. — The body is long, slender and 

 dorso-ventrally compressed (PI. L, figs. 1 and 2). Since we have 

 to do with immature growing worms, it is but natural that the 



