ENTOZOA. 



75 



In tlie Ascaris vertnicularis, the vulva {fy' 32, e) is situated aljout 

 one fourth of the length of the body from the head. 



In the Ascaris lumhricoides the female organs 

 {fig. 31.) consist of a vulva, a vagina, and a 

 uterus, which divides into two long tortuous 

 oviducts, gradually diminishing to capillary 

 ^^\.0\ tubes, which may be regarded as the ovaria. All 



these parts are remarkable in the recent animal 

 for their extreme whiteness. The vulva is situ- 

 ated on the ventral surface of the body, at the 

 junction of the anterior and middle thirds of the 

 body, which is generally marked at that part by 

 a slight constriction. The vagina is a slightly 

 wavy canal five or six lines in length, which 

 passes beneath the intestine and dilates into 

 the uterus. The division of this part soon takes 

 place, and the cornua extend with an irregularly 

 wavy course to near the posterior extremity of 

 the body, gradually diminishing in size; they 

 are then reflected forwards, and form numerous, 

 and apparently inextricable, coils about the two 

 posterior thirds of the intestine. 



In the Nematoidea the male individual is al- 

 ways smaller, and sometimes disproportionately 

 so, than the female. At the season of reproduc- 

 tion the anal extremity of the male is attached 

 to the vulva of the female, by the intromission 

 of the single or double spiculum, and the ad- 

 hesion of the surrounding tumid labia ; and, as 

 the vulva of the female is generally situated at a 

 distance from either extremity of her body, the 

 male has the appearance of a branch or young 

 individual sent off by gemmation, but attached 

 at an acute angle to the body of the female.* 



The evidence of the fertility of the compound 

 cestoid Entozoa, was sufficiently marvellous : 



Ascaris vermicuiaris. that which I havc now to adduce, from a calcu- 

 lation made by Dr. Eschricht, in reference to the 

 Ascaris lumhricoides, the commonest intestinal parasite of the human 



* See Figures of such Nematoid Entozoa in Bremser, Icones Helminthum, 

 tab. iii. fig. 8. 15. ; and Gurh, Lehrbuch der Patholog., Anatomie der Haus- 

 Saiigethiere, tab. vi. fig. 35. 



