ZQOUK'-V 1'OK MKDICAL STUDENTS CHAP. 



lum ber of small rounded blobs of cytoplasm each 



and all Connected together by a common mass of 



entre. The central cytoplasm has increased much 



trge spherical mass the surface of which is covered 



;nd masses already mentioned so that the whole looks 



rry or mulberry. This stage is the sperm-morula 



i to on p. ,-2 (see Fig. 2 1 , A). With further development the small 



n.c. 





sp. 



vd. 



ov. 

 od. 

 ns. 



FIG. 67. 



il organs, nephridia, etc. c.f, Coelomic funnel of male genital duct; 

 . nephridiuiu ; n.c, nerve-cord ; n.o, external opening of nephridium ; ns, nephrostome ; od, 

 codomic f hlCtj m>, ovary; sp, spermathecae ; s.v.l., anterior seminal vesicle ; s.v.II., 



posterior *enin 



rounded U.dio become pear-shaped, their outer ends becoming pointed. 



Later on thc\ become drawn out into fine filaments, the inner thicker 



1 of the condensed nuclear material, the outer composed 



m highly contractile and capable of active flexure from side 



:iallv they break off as complete microgametes or spermato/oa 



ly by the movements of their contractile " tails." 

 matozoa like the eggs lie in the cavity of the coelome but, 

 "n with their small si/.c and active movements, they are 



