JAPANESE PALOLO, CERATOCEPHALE OSAWAI, N. SP. 27 



out and are pressed «gainst the inner side of the body-wall ; 

 while in the atoca these muscles are much thicker and occupy 

 a more internal position in the body. The circular muscle layer 

 is also much reduced in thickness. 



The communicating apertures between consecutive segments 

 become larger as the worm approaches sexual maturity, and 

 admit of a free movement of the genital element from one segment 

 into another. As before indicated, the general body cavity, more 

 or less filled up with either eggs or spermatozoa, extends into 

 the parapodia and sometimes even into the ligula. The main 

 body of the nephridium is pushed into the parapodial cavity by 

 the mass of the genital product. 



The alimentary canal, caudad from the transitional region 

 between the proboscis and the intestine, is much reduced in 

 caliber. The intestinal wall is now much poorer in capillary 

 vessels than before. 



Sexual Producta. — The eggs or the spermatozoa are discharged 

 while the epitocous worms are actively swimming near the surface 

 of the water. The eggs then sink down gradually to the bottom. 

 They are each surrounded by a thick and transparent gelatinous 

 envelope, so that when found in masses, they are separated from 

 one another by a considerable space. They are spherical in shape, 

 with a diameter of 120-150/'-. In color they vary from yellow 

 tu greenish blue. 



The vitellus, surrounded by a delicate membrane at first in 

 direct contact with it, is finely granular and consists of the 

 protoplasm inclosing at least three distinguishable kinds of matter, 

 viz., large oil-drops, small oil-drops and deutoplasmic spheres 

 (PI. II., fig. 22). The large oil-drops, of which approximately 



