TYPICAL THREADWORMS 



3423 



another example of nonparasitic species, we may take the common vinegar eel 

 (Anguillula*) , the magnified figure of which shows that the body is bluntly rounded at 

 the head end, and narrowed and pointed at the tail. The greater part of the body 

 cavity is occupied by the alimentary canal, which traverses it almost from end to 

 end. The oval particles contained in two tubes, which unite and open by a common 

 orifice, are the eggs. This worm appears to live both in vinegar and paste, although 

 it does not seem to 

 derive its nourish- 

 ment directly from 

 either of these sub- 

 stances, but rather 

 from the micro- 

 scopic fungi grow- 

 ing in them. These 

 worms now appear 

 much rarer in vine- 

 gar than former ob- 

 servers have repre- 

 sented; and it is sug- 

 gested that the 



reason of this may VINEGAR EEL. 



be that vinegar is no (Much enlarged.) 



longer made from 



wine or beer; since, in the vinegar obtained from the two latter, there probably 

 remained much sugar and albumen, which form a favorable basis for the growth 

 of fungi, and therefore for the eels. The maturing and propagation of these animals 

 cannot take place in pure vinegar, but only among fungi, where a nitrogenous 

 diet is offered. Vinegar now never contains adult eels, but, at most, larvae and 

 the innumerable little creatures supposed to be seen upon shaking a bottle of 



a. FEMALE OF Rhabditis FORM OF Rhabdonema nigrovenosum ; b. BROOD POUCH. 



(Enlarged.) 



vinegar are, for the most part, nothing but the skin skeletons of these animals. 

 Nearly allied is the wheat eel ( Tylenchus tritici) , which is the cause of a serious 

 disease to the cereal from which it derives its name. In the ears of wheat affected 

 by this worm the grains are misshapen, blackish, and consist of a thick hard scale 

 inclosing a white powdery substance, composed of the larval forms of the worm. If 

 grain in this state is sown in moist ground, it merely rots; but the larvae awake to 



