ENTOZOA. 



75 



In the Ascaris vermictdaris, the vulva {fig. 32, e) is situated about 



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

 -i^, ;j2 In the Ascaris Imnhricoides the female organs 



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

 uterus, which divides into two long tortuous 

 oviducts, gradually diminishing to capillary 

 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 bodj^, 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 botly of the female.* 

 The evidence of the fertility of the compound 

 / cestoid Entozoa, was sufficiently marvellous : 



Ascaris vcrmicuiaris. that which I havc uow to adducc, from a calcu- 

 lation made by Dr. Eschricht, in reference to the 



Ascaris lumbricoides, the commonest intestinal parasite of the human 



* Sec Figures of such Ncmatoid Entozoa in Bremser, Iconcs Helniintliuni, 

 tab. iii. (is- « 15.; and Gurlt, Lehrbucli der Patholog., Anatomic dcr liaus- 

 Saiigethicre, tab. vi. fig. 35. 



