VI 



PHYLUM NEMATHELMINTHES 



291 



nv 



s.lg 



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(Fig. 23-j, r.m.). The muscles of the sheath are circular and act as protractors. 

 At the sides of the base of the proboscis two club-shaped organs, the lemi<i.-i 

 (/;.), hang down into the body-cavity. Their 

 function is quite unknown, but they have been 

 compared with the cervical glands of Nema- 

 todes (p. 284). 



Tn the body-wall run two longitudinal 

 vessels (r. ) containing a granular fluid, and 

 connected with a network of fine canals in the 

 proboscis, bursa, &c. The function of these 

 vessels is not known with certainty : they may 

 have to do with the absorption and circulation 

 of nourishment. 



The central nervous system (Fig. 236, nr.) 

 is represented by a single large ganglion placed 



Fin. -23G. Echinorhynclius gigas. -Disst'o 



tion of male. b. bursa ; c. <jt. cement glands ; 

 I in. lemnisci ; >ic. nerve ganglion ; pr. pro- 

 boscis ; s. Ig. suspensory ligament ; ts. testis ; 

 v. df. vas deferens. (After Leuckart.) 



FIG. 237. Echinorhynchus 



gigas. Dissection of female 

 (semi-diagrammatic), b. bell ; 

 I in. lemnisci; pi\ proboscis; 

 s. fn-ii. swimming- ovaries ; ut. 

 uterus ; i-g. vagina. 



at the base of the proboscis, and sending off nerves in various directions. 

 In the male there are also two ganglia supplying the reproductive organs. 

 Organs of sense are wholly absent. 



u 2 



