GENEEATIVE OEGANS OE VERMES. 191 



The form-elements of the sperm are generally rounded or 

 elongated bodies, from which a fine movable flagellmn projects. 

 The Nematodes again are peculiar in this matter ; their seminal 

 elements, like the ova, being budded off from a rhachis. The cells 

 thus formed increase in size, and form cell-like bodies, which 

 perform amoeboid movements, but do not develop a flagellum. 



In many Annulata the seminal filaments are united into masses 

 of definite form (spermatophores) in special parts of the male 

 efferent ducts ; these are passed as such into the female apparatus. 

 Many Scoleina have spermatophores of this kind, which are merely 

 formed by agglutinated seminal filaments (Tubif ex) . In the Hiru- 

 dinea the spermatophores are provided with a special covering. 



