STRUCTURE OF EARTHWORM ALLIED TO NEMERTODRILUS. 573 



worm (fig. 18) the reverse is the case ; the interspaces between 

 the gizzard are very much longer than, about three times as 

 long aSj the gizzards. 



The intestine is lined by a columnar epithelium, the cells of 

 which are still loaded with spherical granules ; they resemble, 

 in fact, the cells of the intestine in the advanced foetus of 

 Acanthodrilus. The interior of the intestine seems to indicate 

 that the young worm had not yet commenced to swallow the 

 soil in which it was found ; the intestine contained a granular 

 substance, which presented the appearance of a coagulated 

 albuminous fluid ; in this were embedded a large number of 

 setse of small size ; the structure of the setse showed that they 

 probably belonged to the same species ; at least there was 

 nothing to indicate that they did not. So far as my experience 

 at present allows me to say, it is not possible to distinguish the 

 setse of the Eudrilidee from those of the Lumbricidse, and, in- 

 deed, of most other groups of earthworms. The question is. 

 How did these setse get into the intestine of the young worm ? 

 I noticed in the body-cavity of the same individual a few 

 setse embedded among the peri-intestinal coelomic cells ; these 

 were evidently setse of the same individual that had become 

 freed into the body-cavity ; if they can work their way through 

 the intestinal epithelium we have an explanation of how they 

 come to be found in the cavity of the intestine. It seems 

 more probable, however, that they were originally swallowed, 

 and in this case it appears likely that the cocoon con- 

 tains up to a comparatively late period more than 

 one developed embryo; the individual or individuals 

 which succeed in reaching the full term of their development 

 must feed upon the others when alive or upon their dead 

 bodies. 



The structure of the gizzard in longitudinal section is shown 

 in fig. 18. The circular muscles appear to be derived from 

 columnar cells, the nuclei of which are shown; whether these 

 cells are produced by the division of the hypoblastic cells, or 

 from the splanchnopleure, which is most probable, I am unable 

 to say. The muscular fibres themselves are arranged in a 



