GONAD 



269 



large round nucleoli aiv ] .resent, frequently corresponding in number 

 with the lobes of the nucleus. 



The embryonic gonad during the stages which have been described 



FIG. 140. Origin of the gona.l in Atnhljiatoma. (After Schapitz, 1912.) A. 7-8 days 

 after fertilization ; B, 10 days ; C, 12 days ; D, 18 days ; E, 17-18 days ; F, 19 days ; 

 (!, just after hatching. 



it.n.il, arrhinr|ilirir duct ; </, ^onad ; g.r, genital riil-f ; /.<!, luti-ral mesodi-nn ; my, niyotonn- ; .<;rfr, 

 siil.'tiicliiioi-ofl.-. At in Fi-. I) is st-cn one of the heavily yolkt-d n-lls \\hicli an- int<T]>irti'.! by soim- 

 as arrrssorv ^uiun-\ tea 



is not as a rule continuous from end to end. On the contrary it 

 consists of isolated pieces and these in many cases show distinct 

 traces of metameric arrangement, the pieces being directly opposite 



