634 DB. H. CHAELTON BASTIAN ON THE ANATOMY AND PHTSIOLOGT 



lower lobe of right band ; rf, main vessel from which branches indicated by 

 dark lines are given off; e, central cavity of lemniscus; f,f, space occupied 

 by dorsal muscles ; f, f, ditto by ventral ; g, cellulo-granular layer of inte- 

 gument, having no developments in mid-dorsal and ventral region ; h, chiti- 

 nous portion of integument. 



Fig. 11. Transverse section of anterior extremity of same, in the situation of its central 

 nervous system. Parts same as in %. 1, except a, which here represents the 

 toterior excretory duct slightly posterior to its point of communication with 

 the exterior, near the bases of the two ventral head-lobes. 



Fig. 12. Transverse section of the posterior extremity of the male of same species, just 

 above ano-genital cleft. References same as in Plate XXIII. fig. 4, and Plate 

 XXV. fig. 7. The most notable points are the extreme size of the latero- 

 ventral muscular bands {k, k), and the entire obliteration of the lateral lines. 

 The two dorsal muscles appear as one band only, equalling in size each one 

 of the mdely separated ventral muscles, which are now more lateral in 

 position. 



Fig. 13. Transverse section through oesophageal region of Ascaris spicuh'gera : — a, a, 

 lateral bands, each having a horizontal fibrous septum ; b, anterior portion of 

 lemniscus, with its axial vessel and radiating branches; c, oesophagus; d, 

 anterior intestinal caecum ; e, coagulated material, containing small cells or 

 granules, in general cavity of body. 



Fig. 14. Transverse section of same near the middle of lemniscus, showing its connexion 

 with the lateral bands, as in fig. 10. In this species the lemniscus is thicker, 

 contains only a very small central cavity, and the main excretory vessel 

 occupies its axis, giving off inosculating branches on all sides. 



Fig. 15. Section of same, nearly opposite the posterior termination of lemniscus : — a, 

 the very thick chitinous portion of the integument; b, lemniscus near its 

 termination, still shovdng axial vessel. 



Fig. 16. Middle portion of lemniscus of Ascaris spiculigera, showing its small, broadly 

 fiddle-shaped central cavity, and deviation of central vessel from its axial 

 position. 



Fig. 17. External layer of integument of same. 



Fig. 18. Integument of same, more deeply focused. 



Fig. 19. Section through the middle of the body of a female Spiroptera obtusa, showing 

 the extreme inequality in the size of lateral bands (a, a) : — b, b, median lines ; 

 c, intestinal canal ; d, d, two ovarian tubes. 



Fig. 20. Section close to anterior extremity of same, showing a ventral communication 

 between the lateral bands, though no axial vessel could be detected. 



Fig. 21. Section of muscle-cells and integument of same species: — a, thick chitinous 

 portion of integument; b, very thin cellulo-granular layer; c, contractile 

 portion of muscle-cell ; d, medullary and bladder-like portion. 



