26 



ring, the ventral cord, and the accessory ganglia. The 

 encephalon, which takes the place of the brain of higher ani- 

 mals, consists of two masses of ganglia, situated on the sides of 

 the oesophagus. From these, two broad cords pass inwards 

 and meet to make up an oesophageal ring, two large branches 

 from which run round the stomach and unite to form the 

 ventral cord. 



The ventral cord runs undivided in the male, while in the 

 female it divides and re-unites, to encircle the vagina. Finally, 

 it branches, in both sexes, at the commencement of the rectum, 

 into two large caudal ganglia. A transverse band here com- 

 pletes the anal ring. There is also a large, remiform ganglion 

 at the lower end of the anus. From these ganglia and cords, 

 peripheral branches pass to the various organs of the body. 



Muscular System. 



The muscular system is very highly developed. Four 

 longitudinal muscles, two dorsal, and two ventral, run the 

 whole length of the animal, just beneath the corium. The 

 different organs are freely supplied with muscle -fibres, but 

 transverse fibres are almost entirely wanting except in the 

 female reproductive organs 1 . Between the four longitudinal 

 muscles are four stripes, or bands, known as fat-canals ; in 

 young individuals they contain fat, which is gradually absorbed 

 as they reach maturity, but their precise function has not been 

 established. 



Reproductive System. 



Male : The semen-forming organ, or testis, is a fairly 

 simple, twisted tube, blind at one end. It occupies the 

 posterior third of the animal, and, winding over the 



1 The musculature of these or- font saillie sur le contour de 1'organe. 



gans was minutely observed and On les voit se raccourcir et s'allonger 



described by CLARAPEDE : " C'est pendant les mouvements peristal- 



chez 1'oxyure de rhomme (Oxyuris tiques du tube generateur. II est 



vermicnlaris) que nous avons pu bon de dire que les mouvements 



etudier le plus commodement les peristaltiques de 1'uterus et du 



muscles de 1'uterus et du vagin. vagin s'executent avec une vivacite 



Les fibres musculaires y sont dis- toute particuliere chez YOxyuris 



posees transversalement autour du vermicular is." (CLAPAREDE, E., 



tube generateur a une certaine De la formation et de la fecondation 



distance les unes des autres, et des oeufs chez les vers nematodes, 



forment des anastomoses entre elles. Geneve, 1859, p. 18.) 

 Ces fibres sont si epaisses qu'elles 



