THE TREMATOD A. 55 



one is especially remarkable, large and vesicular, which 

 commences close to the edge of the collar, passes down- 

 wards as fai' as the abdominal acetabulum, and thence 

 sends down a branch on each side of it, almost straight 

 to the posterior border of the body. As this organ is 

 composed of vesicular sacculi which do not open into each 

 other, nor form any common canal, but on the contrary 

 appear to open into a cavity situated beneath them, I have 

 looked upon it as a liver. From the oral orifice a canal 

 may be seen passing to the anterior end of this organ, 

 but not to enter it ; since this canal must be an oesopha- 

 gus, I am compelled to assume that a stomach passes 

 under the liver-like organ, and is conformable to it. Other 

 winding organs, whose real natm^e is not yet clear to me, 

 descend on each side of the body ; they are partly filled 

 with numerous very minute equal sized globules or cells. 

 I have only casually been able to trace their course up- 

 wards as far as the sucker ; whether they terminate here, or 

 whether it is that they form a canal, which under certain 

 conditions of illumination may be observed, as a trans- 

 parent slightly vending streak, between the branches of 

 the liver-like organ, and which appears to terminate in 

 the caudal cavity, I must leave undetermined. In the 

 upper part of their course they contain small globules, 

 and form as it were several reticulations, and also as it 

 appears constitute a ring around the pharynx. 



The tail is very long, being about the same length as 

 the body, to which it is attached in a very shallow depres- 

 sion. It is extremely moveable, contractile and extensible, 

 and presents on the sides alternate depressions. It is 

 formed of several membranes or tubes placed one within 

 the other, of which the outermost is a very transparent 

 epidermis, under which is a tolerably thick membrane 

 furnished vnth transverse muscular fibres or strits, and 

 between each pair of these transverse fibres is placed a 

 globular vesicle which appears to be a mucous follicle or 

 gland ; the innermost tube is opaque and of firmer con- 

 sistence, it contains the longitudinal muscular fibres, and 



