ASCARIS LUMBBICOIDES. 307 



itself, and also twisted round the lower part of the intestinal tube. It 

 may, however, be easily unravelled beneath water, and, when fully 

 extended, will reach nearly a yard in length. The internal blind extre- 

 mity constitutes the narrowest part of the tube, which, after a gradual 

 but inconsiderable increase in width, forms the bulk of the testis 

 proper, and then subsequently widens out to form the vas deferens. 

 The latter suddenly terminates at the summit of a somewhat club- 

 shaped pouch, which is usually distended with spermatic particles. 

 Towards the lower part, the pouch itself is also suddenly con- 

 stricted, and enters a thick muscular sheath, within which the two 

 penes or spicula are lodged during their retraction. Ordinarily, 

 this seminal reservoir is about one inch and a half in length. The 

 spicules are arcuate and rather bluntly pointed, but there is no 

 central groove or orifice at their extremities, as some had led us to 

 beheve. As regards the reproductive organs of the female, they 

 consist of the ordinary parts, but the relative development of these 

 is very remarkable. Thus, the uterus and vagina, taken together, 

 are about half an inch in length, but the former divides into two 

 long uterine horns, each of them measuring at least four inches 

 long. At their inner ends they suddenly become narrowed to form 

 two long ovarian tubes which coil upon themselves and around 

 the intestinal canal in a very tortuous manner, terminating finally 

 in extremely narrow coecal extremities. If either of the tubes be 

 carefully unravelled, it will be found to measure about four feet in 

 length. In full-grown individuals, one constantly finds these canals 

 filled with ova in every conceivable stage of development, from the 

 condition of a simple free nucleated germ, situated at the coecal 

 extremity, to the finely-granular yelk of the perfect egg, which is 

 just about to emerge by the vaginal outlet. In Ascaris megaloce- 

 'phala, I have seen the spermatozoa in immediate contact with the 

 egg- germs, constituting, according to Nelson, the very act of im- 

 pregnation ; but into the details of this process I do not now enter, 

 reserving what I have to say on this point until we are considering 

 the sexual peculiarities of Ascaris mystax. 



