102 CGELELMINTHA. 



The oviduct formed by the junction of the oviferous canals which 

 embrace the oesophagus, is very narrow at its commencement, but 

 after running backwards for some distance it dilates a little, and, 

 becoming much convoluted, it winds around the alimentary tube 

 in numerous and extremely complex gyrations (d). Towards the 

 lower third of the body, the coils become less numerous and more 

 distant from each other, and are seen to contain brown ova in scat- 

 tered masses, until at length the oviduct assumes a course parallel 

 to that of the intestine (e), and accompanies it to the anus, in the 

 vicinity of which it terminates. 



The ova are of a firm resisting texture, and do not lose any 

 of their form or contour by drying ; hence they may preserve their 

 vitality for a long period under very different circumstances, and 

 be ready to assume the actions of developement when deposited in 

 a fit situation. 



(137.) In the male Linguatula, the structure of the generative 

 apparatus is very simple. Two long convoluted tubes, which float 

 loosely in the abdominal cavity, secrete the seminal or impreg- 

 nating fluid ; and these tubes, which may be called the testes, ter- 

 minate by forming a single canal or vas deferens, leading to the 

 external organs appropriated to sexual union, which are two fili- 

 form appendages found in the neighbourhood of the head, through 

 which the fecundating secretion is expelled. 



(138.) The only other example which will be necessary to illustrate 

 the structure of the CCELELMINTHA, is an evident approximation to 

 the annulose type of animal organization. The Ascaris lumbri- 

 coides indeed, as its name imports, so strongly resembles some of 

 the annelida in its external configuration, that the zoologist who 

 should confine his attention to outward form alone, might be 

 tempted to imagine the affinities which unite them much stronger 

 than a comparison of their anatomical relations would sanction. 

 This entozoon is found in the intestines of many animals, and is 

 endowed with some considerable capability of locomotion adapted 

 to the circumstances under which it lives ; for in this case the 

 worm, instead of being closely imprisoned in a circumscribed space, 

 may traverse the entire length of the intestines in search of a con- 

 venient locality and suitable food. 



(139.) In accordance with such an enlarged sphere of existence, 

 we observe muscular fibre distinctly recognisable in the tissue which 

 composes the walls of the body, not as yet indeed exhibiting 

 the complete characteristics of muscle as it is found in higher 



