OF THE NEMATOIDS, PARASITIC AND FEEE. 633 



PLATE XXVI. 



Fig. 1. Transverse section of the anterior extremity of Ascaris marginata through its 

 oesophageal (nervous) ring : — «, a, lines seen in chitinous portion of integu- 

 ment; b, b, b, b, the four principal communications of muscles with sheath of 

 oesophageal ring ; c, c, ganglion-cells in substance of ring. 



Fig. 2. Section of same slightly posterior to arch of excretory vessels : — a, a, unequal- 

 5 sized lateral bands ; b, b, unequal-sized axial vessels ; c, oesophagus ; d, ante- 



rior intestinal caecum ; e, e, space occupied by dorsal muscles ; f, f, ditto by 

 ventral. 



Fig. 3. Section of three muscle-cells of same species. 



Fig. 4. Transverse section of anterior extremity of Ascaris mystax, slightly posterior to 

 arch of excretory vessels: — a, a, lateral integumental alae; b, oesophagus; 

 c, c, space occupied by dorsal muscles ; d, d, ditto, by ventral ; e, e, narrow 

 projections of chitinous layer into substance of lateral bands; f, f, axial 

 vessels. 



Fig. 5. Transverse section of intestinal canal of the same : — a, thick internal structure- 

 less cuticle ; b, columnar hepatic cells ; d, thin external structureless mem- 

 brane. 



Fig. 6. Anterior half of body of Ascaris osculata, slit up in dorsal region (X 3), showing 

 position and nature of so-called " lemniscus," developed from left lateral band 

 (a) and the course of the main excretory canal (b) which communicates with 

 the exterior at c : — d, right lateral band. 



Fig. 7. Portion of the lemniscus from the situation indicated by e in last figure, more 

 highly magnified : — a, portion of the main excretory vessel, from which are 

 given off innumerable, inosculating, thin-walled branches, in the middle of 

 the delicate cellulo-granular material of which this development is composed. 



Fig. 8. Showing the narrow termination of the lemniscus (a) on the side of the bilobed 

 lateral band (b), and also the gradual termination of the main excretory 

 vessel (c). 



Fig. 9. Transverse section of anterior extremity of Ascaris osculata, through the lateral 

 cervical pores (a, a), showing the very unequal size in this region of the two 

 bilobed lateral bands (b, b), and the single vessel (c), just as it is about to 

 leave the large lower lobe of the left band in order to reach the mid-ventral 

 pore. The intestinal caecum does not reach so far forward as the situation of 

 this section. 



Fig. 10. Transverse section of the body of Ascaris osculata, slightly posterior to termi- 

 nation of oesophagus: — a, intestinal canal with extremely thick glandular 

 walls ; b, b, bilobed lateral bands, nearly equal in size ; c, lemniscus project- 

 ing from the lower lobe of left band across the ventral region of the body, its 

 free extremity being connected by some delicate fibro-cellular tissue with the 



MDCCCLXVI. 'y 4 S 



