26 ART S. 1. IKE DA : THREE NEW AND 



vessel id.v.), at a j)oint a short distance in front of the junction 

 of the posterior end of the oesophagus with the crop ((??'•). I 

 shall return to this suspensory membrane in relation with the 

 dorsal vessel. 



The œsophagus (fig. 23, œs.) is a narrow muscular-walled 

 tube 2-4 mm. wide and which, when stretched out, may measure 

 200-300 mm. in total length. From the hind end of the pharynx 

 it proceeds posteriorly down to about the middle of the body 

 length ; then it makes a sharp bend forwards, thus bringing 

 about a narrow U-like loop. The ascending limb of the loop, 

 on reaching a point a short way behind the posterior end of the 

 suspensory membrane {d.m.) of the dorsal vessel, makes another 

 sharp bend but this time backwards. Just at this point the 

 oesophagus passes over into the third section of the alimentary 

 canal, the crop (c?\). The first part of the oesophagus from the 

 pharynx to the posterior end of the suspensory membrane of the 

 dorsal vessel is, as before indicated, connected with the body- 

 wall by the right lateral mesentery. The same part is further 

 peculiar in that it is internally provided with a typhlosole-like 

 structure projecting into the lumen along the mid ventral line 

 (fig. 35, ts.). In addition to the above mentioned mesentery, the 

 oesophagus is fixed in its entire length by a series of muscular 

 strands which spring from the body-wall close to the ventral 

 nerve-cord on the left side. 



The crop (fig. 23, or.) is, like the foregoing section, a narrow 

 tube but is characterized by the internal surface being beset with 

 villi-like papillae. In the empty state it is 70-90 mm. long and 

 3-4 mm. wide. It takes a linear course and is furnished through- 

 out its length with the ventral mesentery {v.m.) which is inserted 

 on the ventral body-wall close to, and on the left of, the nerve- 



