THREADWORMS. 81 



cularis is so well known to most of you that I need 

 not minutely describe it; moreover a detailed account 

 , of the anatomical peculiarities of this parasite will be 

 (/T found in my larger work on Entozoa,with explanatory 

 figures. If an ordinary full-grown female worm be 

 submitted to microscopic examination, even the em- 

 ployment of the one-inch achromatic objective glass 

 will reveal the presence of a multitude of eggs 

 internally. Under higher powers, say the quarter 

 inch, the contents of the eggs will be found to 

 display every variety of character, according to the 

 positions which they severally occupy within the 

 uterine tubes of the maternal body. As Claperede 

 and myself long ago pointed out, and quite inde- 

 pendently, the most advanced eggs do not exhibit 

 vermiform or filiform embryos in their interior (as 

 Kuchenmeister erroneously figured and described 

 t n them), but thick bodied, tadpole-shaped larvae. 

 * i After extrusion from the body of the parent, how- 

 1 ever, they soon assume the vermiform character, 

 that is, when they are placed under conditions 

 suitable to their further development. 



The researches of Yix and Leuckart have shown 

 that " one needs only to expose the eggs to the action 

 of the sun's rays in a moistened paper envelope, when 

 at the expiration of some five or six hours the tadpole- 

 shaped embryos will have already become slender 

 elongated worms. At this stage they are not 

 altogether unlike the sexually mature oxyurides in 



