Introduction to A nimal Morphology. 2 1 7 



of ovaries are small, behind the testes, having- two 

 wide-mouthed oviducts behind them, attached to the 

 body wall ; with these communicate round sperma- 

 thecal sacs lying 1 near the testes. The oviducts open 

 anteriorly to the penis. In the earthworm six segments 

 in advance of the clitellum are the copulatory, ad- 

 . e organs, which are modified, imperforate, loco- 

 motor seta\ Most other worms have no special 

 genital ducts, but empty the sex-products through the 

 segmental organs. The ova may form on the inner 

 wall of the dissepiments, or of the body cavity 

 (Tomopteris), or in 1-3* pair of ovaries, and the semen 

 in 1-4 pair of testes. Each sex-organ has a vessel or 

 a cellular string in its axis, from which the sperm 

 cells or eggs bud. 



Th either single or in clusters Fig. 3- 



within capsules, cocoon-like in Lumbricus, 

 pillar \renicola, with copious or no 



albumen (Tubifex). A few (Kunicea, Syllis, 

 Cirrhatulus) arc viviparous. Lumbricus de- 

 velops directly. Most of the others have in- 

 direct pment by a dissimilar larva. 

 This has no gastrajal stage, according to 

 some rs, and may be ciliated at the 

 mity (Telotrochal), at one end only 

 n I'uiynoc), or at both ends 

 hitruchal as in Tm-brlla), or ciliated in 

 the m; d as in Spinrluvtnp- Polytro 



iv wreaths of cilia (Poly- 

 trochi:'. . -T- 3)- I has five ciliary 



1 !]H)(li.l. 



at the back of tlir 

 lobe b. 



