412 ANIMAL PAEASITES. 



muscular structure, as a passive one by the contraction of 

 the general muscular system of the body. As regards the 

 four whitish streaks on the sides of the worm, of which 

 two are broader than the others, I have already stated, that 

 these streaks prove to be cylindrical cords, in the interior of 

 which a sort of hollow canal is detected, which appear to present 

 almost dendritic diverticula. There is no doubt that these cords 

 are hollow canals, and in fact the remains of the fat-canals. 

 In Ascaris lumbricoides these cor*ds may be recognised as hollow 

 canals throughout the whole subsequent period of life. The 

 peculiar dendritic appearance in the interior of this streak is 

 certainly due to the unequal contraction and the collapsing of 

 the walls of these retrograding canals. 



The males and females may be distinguished during life, even 

 by their form and external appearance. The female has the 

 abdomen slender, fusiformly pointed : the male is bent round like 

 a hook, and sometimes exhibits, at a short distance from the tail, 

 a pair of white, delicate, projecting hairs, which are the protruded 

 penis. The female shows two ; but frequently, when one ovary 

 runs rather further back than the other, only one thick, white 

 cord, usually somewhat thinner posteriorly, which terminates 

 about | 1 inch, or 1^ inch from the caudal extremity, and is 

 surpassed posteriorly by a brown cord, the intestine. The male 

 exhibits a simple, white, tubular sac, constantly becoming wider 

 posteriorly, which reaches to the anus, lets nothing more be seen 

 of a brown intestine, and may be traced nearly to the extremity 

 of the tail, as it opens here with the anus. If the female be 

 pressed upon the body, or allowed to swell in water, a prolapsus 

 of thin tubes (ovaries) and a discharge of a milky mixture (eggs) 

 takes place in the anterior half of the animal from the vaginal 

 orifice. If a male be pressed, a milky juice (the seminal globules) 

 flows out in the neighbourhood of the anus, without the occur- 

 rence of a rupture or prolapsus, which are only produced very 

 late, if at all, when the male is laid in water. 



There is an error of Werner's to be mentioned here, which Wedl 

 quotes ; he says the penis may swell up into a club, because it 

 stands in connection with a thick seminal duct. This could only 

 be the case if the penis of our Ascaris were perforated, and 

 seminal corpuscles could pass into it. That this is impossible 

 I have already mentioned. The matter is very easily explained. 

 In Werner's case, the apex and the base or root of the penis were 

 still within the external orifice of the sexual organs/ but the 



