TREMATODES OF AUSTRALIAN BIRDS. 231 



truncated. The cuticle is beset with numerous fine spines 

 which scarcely project on the surface and are only to be 

 seen in sections. 



The suckers are large and strong, especially the ventral, 

 which is more than twice as large as the oral. They are 

 both circular in outline, the latter 0*54 mm. in diameter, 

 the former 1*26 mm. They are separated by an interval 

 of 0*75 mm. 



Alimentary canal. — There is no pharynx of the usual 

 form found in trematodes, but the wall of the oesophagus, 

 tubular in form, is provided with muscular layers. There 

 is an outer layer of circular and an inner layer of longi- 

 tudinal fibres. Both these muscular sheets are directly 

 continuous with similarly arranged layers in the oral sucker, 

 though the well marked and thick layer of radial fibres 

 present in the sucker appears to be absent from the 

 oesophagus. MacOallum mentions (34 ' p - 699) that " the muscu- 

 lature of the (oral) sucker is composed of three layers, 

 meridional, radial, and equatorial or arcuate. The pharynx 

 similarly constructed and provided with a thick cuticular 

 lining, " etc. This corresponds pretty closely with what I 

 find in C. australiense, except that, in the absence of the 

 usual barrel-shaped pharynx with thick muscular walls, I 

 prefer to call the tubular structure with thin sheets of 

 muscular tissue in its walls "the oesophagus." Braun^ 8 ' 1 - 8 ) 

 seems to view MacOallum's statement about the muscular 

 layers with some doubt, but my finding them in the form 

 under investigation here may be looked upon as confirma- 

 tion of MacCallum's observations. 



From the oesophagus the intestinal limbs are directed at 

 first laterally, and reach a point halfway between the middle 

 line and the side of the body. Here a sharp turn is made 

 to run backwards more or less parallel to the sides of the 

 body, the two limbs coming nearly together at a point just 



