STRUCTURE OF EARTHWORM ALLIED TO NEMERTODRILUS. 549 



14 onwards is ciliated ; its epithelium is thrown into regular 

 longitudinal folds ; the cells are tall and columnar, and the 

 muscular coat is of an appreciable thickness. 



The oesophagus is extremely vascular ; in longitudinal and 

 transverse sections its walls have from this cause a moniliforra 

 appearance (fig. 16). So far as 1 could make out, the plexus of 

 blood-vessels which lies immediately below the epidermis was 

 nowhere a sinus, although the individual vessels were so close 

 together as to give this appearance; still a more careful 

 examination showed the longitudinally running connecting 

 branches between the much wider circular vessels. 



The three gizzards are in Segments 23, 24, and 25 — one 

 gizzard to each segment; they are not all three directly con- 

 tinuous, but are separated by a certain amount of soft-walled in- 

 testine. The soft-walled portion occupies the anterior part of 

 each gizzard segment ; posteriorly, the gizzard comes into con- 

 tact with the septum. 



The width of the crop gives the gizzards the appearance of 

 being strung, as it were, upon the intestine ; but that the 

 crop belongs to the oesophagus and not to the intestine is shown 

 by the fact that it has no typhlosole. 



The intestine is furnished with a typhlosole which is of a 

 somewhat unusual form. From its very commencement to as 

 far back as Segment 37, three folds can be seen on a dissection — 

 one median, and one on each side. The median fold corre- 

 sponds, of course, to the dorsal vessel, and is of about thrice the 

 vertical diameter of each of the two lateral folds. All three 

 folds were quite conspicuous in dissections from their red 

 colour. After the 37th segment the two lateral folds disap- 

 peared, but the median typhlosole continued on to near the 

 end of the body. 



In dissected worms, both fresh and after preservation, the 

 intestine was of a rich mahogany brown colour, quite different 

 from the colour of our British Lumbrici; Neraertodrilus 

 and some of the other Eudrilids agree with the present species in 

 this particular, which is due to the abundance and darkness of 

 the granules in the chloragogen cells. 



