PRESERVATION OF THE EGGS OF HELMINTHES 



113 



The eggs of Acanthocephales are very characteristic. They are 

 spindle-shaped, though sometimes oval, and are enclosed in several 

 transparent shells of different thicknesses. When deposited they 

 contain a finished embryo, of which, however, the hook is the only 

 recognizable feature (fig. 43). 



FIG. 39. Egg of Oxyuris 

 vermicular is, L. 640 : 1. 



FIG. 40. Left, egg of Ascaris lumbricoides, 

 400 : 1. Right, egg of Ascaris canis (L.). 



Eggs of Helminthes should be preserved on a glass slide, the cover- 

 glass being raised by means of supports of a suitable thickness. They 

 are fixed in alcohol, which should be repeatedly changed and is finally 



FIG. 41. Egg of Eustrongylus gigas 

 (Rud.). The upper figure shows the flat 

 surface ; the lower figure shows the egg 

 in section. 



FIG. 42. Trichocephalus trichiuris (L.). a, 

 Egg, very much magnified, b, Female, c, 

 Male. Sp., Spiculum. (Slightly magnified.) 

 After Glaus.) 



replaced by a mixture of glycerine and alcohol. If carefully treated 

 the eggs rarely wrinkle. The glycerine and alcohol stages are carefully 

 graduated until the eggs lie in pure glycerine, which is replaced with 



