42 



The Rot in Sheep. 



Examined with a low magnifying power, the oral sucker and 

 oesophagus appear to be continuous as a simple funnel-shaped 

 body, situated immediately above the bifurcation of the digestive 

 tube. They will, however, be found to be far more complex in 

 their arrangement when carefully dissected under the microscope. 



Fig. 6. 



Oral Sucker and GEsophagean Sphincter. Highly magnified. 



The sucker itself (a^fig. 6) is formed on the same plan as the 

 ventral one, with its raised and rounded border, and sunken centre. 

 Directly at the bottom of the concavity an opening leads to the 

 oesophagus {h,ftg. 6), a short tube represented as slightly dilating 

 inferiorly, where it divides into two principal branches (c). 

 From its commencement to its termination the oesophagus is 

 surrounded with bundles of muscular fibres (dd). These fibres 

 run lengthways by the side of the tube, reaching from its upper 

 to its lower part, and so embracing it as to form an elongated 

 sphincter. The artist, by intersecting lines at the lower part 

 of the oesophagus, has attempted to show that the fibres surround 

 the canal, and with the object also of bringing it into view, 

 he has represented a portion of the sphincter as being cut away 

 in front. Although the oesophagus lies in the centre of the 

 muscular fibres, these are not equally developed all around it, 

 but are stronger on the lateral parts than on the back or front. 



Early after commencing investigations into the anatomy of the 

 liver-fluke — now several years since — we had an opportunity of 

 seeing the entozoon eject from its oral opening considerable por- 

 tions of the contents of the digestive tubes. We first witnessed this 

 on placing one, obtained directly after slaughtering a sheep, in 

 some tepid water. The creature almost immediately elevated its 

 head, and, with a leech-like action, ejected a portion of the con- 

 tents. This was quickly followed by two other similar ejections, 

 soon after which it died. Since that time we have witnessed the 



