278 ERNEST WARREN. 



(Figs. XII, XV). Commonly the scales of the adult are about 

 3 fx in height. The cuticle is thickest over the hinder region 

 of the body, and consists of two layers, — an inner vacuolated 

 portion, and an outer, more homogeneous layer. The scales 

 may be perfectly solid and continuous with the outer homo- 

 geneous layer (Fig. XVI), or they may be vacuolated and 

 appear like bubbles ^ on the surface of the cuticle (Fig. 

 XVII). The cuticle and scales were very inconspicuous in 

 the free young individuals. 



The general body parenchyma beneath the cuticle is of the 

 usual type. The so-called epidermal cells (Fig. XVI, ep. c.) 

 are exceedingly irregular in distribution and widely scattered: 

 they send out numerous branching threads, some of which 

 extend to the periphery and form the thin protoplasmic layer 

 (_/). I.) directly beneath the cuticle. The musculature tends 

 to be rather feeble ; the circular muscle-fibres (c. m.) are 

 arranged in a single layer immediately below the protoplasmic 

 layer. The longitudinal muscle-fibres (/. vi.) are very much 

 stouter and are less regularly arranged. The rest of the 

 body parenchyma consists of (1) large branching cells with 

 perhaps inter- and not intra-cellular spaces filled with granu- 

 lar fluid [b. c), and (2) large rounded vesicular cells {v. c). 



The Alimentary Canal. — The mouth in the middle of 

 the anterior sucker leads into a very short and thin-walled 

 pre-pharynx. The pharynx is small, and passes into a quite 

 exceptionally long oesophagus, which extends backwards to 

 about the level of the hinder part of the posterior sucker. 

 Surrounding the oesophagus there can be seen a few glandu- 

 lar cells, the so-called salivary glands. The two gut casca 

 are comparatively short, being rather less than half the 

 total length of the body (Figs. II, III). The cells of the 

 gut are set on a basement membrane ; those of the oesophagus 

 tend to be somewhat flat, while those of the ca'ca are some- 

 times so tall as to leave little lumen. Directly outside the 



• II, is very probable that these structures are au arlilicial production 

 causeil by the action of the reagents enii)loycd. Fide Brauu's " Trematoden," 

 Bronn's ' Thierreicli,' Bd. iv, p. 593. 



