PHYLUM CHORD AT A 



119 



funnels (nst), into the coelome ; a short cUsbance from the funnel 

 each gives off a blind pouch, which dilates at the end and forms a 



w«^ 



ms.Th.d' 



7rtb,jh,A 



Fig. 791. — Diagrams illustrating the development of the urinogenital organs of Craniata. 

 A, development of pronephros and pronephric duct ; B, atropby of pronephros, development 

 of mesonephros ; C, differentiation of pro- and raeso-nephriu ducts ; D, development of meta- 

 nephros, male type; B, female type. al. hi. allantoic bladder; an. anus; cL cloaca; gon, 

 gonad; int. intestine; m. c. Malpighian capsule; ms. n. d. mesonephric duct; ras, npli. 

 mesonephros; mt. v. d. metanephric duct; int. nph. metancphros ; nst. nephrostome ; or. 

 ovary; -p. n. d. and sg. d. pronephric duct; p. nph. pronephros; (. testis; v. e, vasa 

 efferentia. 



Malpighian capsule (m. c), and a branch from the aorta entering it 

 gives rise to a glomerulus. 



