72 



ENTOZOA. 



surface of the neck, but cease at a little distance apart on either 

 side of the longitudinal band. Speaking generallj, therefore, the 

 integument consists of a finely laminated epidermis, and a tolerably 

 dense true corium, the latter being Uned internally by two 

 muscular layers — an outer one with transversely arranged fibres, 

 and an inner one with longitudinal fibres. In addition to these, 

 according to Wilson, " the lips are moved by means of a strong 

 apparatus of longitudinal muscles." 



The digestive apparatus conforms for the most part with the sim- 

 ple arrangement so prevalent in nematodes. The mouth is described 

 by Wilson as being quadrilabiate and orbicular, " each of the lips 

 being armed by two short conical hooks, which are curved inwards 

 towards the oral aperture." These hooks do not appear to have 

 been noticed by any other observer. The mouth itself leads into 

 a narrow oesophagus, which is straight at first, but very soon 

 becomes contorted, so as to display a series of regular convolu- 

 tions, having a monihform or beaded appearance (a, Fig. 3). To 

 myself these regular foldings appeared quite convex at their 

 borders, but Wilson says they are angular, " being retained in 

 their position by a number of delicate ligamentous bands, which 

 stretch from the outer wall to the inner surface of the integu- 

 ment." Wilson here evidently refers to the structures described by 

 Kuchenmeister, as forming " a mass of small triangles, with their 

 apices turned towards the intestine," and serving to connect the 

 tubes with the parietes. Both Kuchenmeister and Wilson have 

 noticed certain glandular structures in connection with the alimen- 

 tary canal, but their nature is not clearly made out ; and I have also 

 observed in the capillary portion a regular series of oval cellules {d, 

 Fig. 3), forming a loosely attached parenchyma within the perivis- 

 ceral space. Speaking of the continuation of the tube, Wilson remarks 

 that " the sacculated character of the first portion of the alimentary 

 canal, and the strongly-marked bands which tie the dilatations to 

 the inner surface of the integument, constitute together a well- 

 defined line of demarcation between the capillary portion and the 



