URINOGEN1TAL ORGANS. 



297 



and only 'secondarily communicate with the segmental 

 duct (Fig. 234A to c, and Fig. 235). 



Each pronephric and niesonephric tubule is made up of the 

 following portions (see Fig. 234A) : (1) a funnel-shaped ciliated 

 aperture, communicating with the body-cavity (peritoneal funnel, 

 nephrostome, Fig. 234A, ST) ; (2) a rounded mass of capillaries 



FIG. 234A. DIAGRAM OF THE (SECONDARY) CONNECTION OF THE MESONEPHRIC 

 TUBULES WITH THE SEGMENTAL DUCT (SG). 



The two anterior tubules are already connected with the duct, while the two posterior 



have not yet reached so far. 

 tiT, nephrostome ; M, glomerulus ; DS, coiled glandular tubule ; ES, terminal 



portion of latter. 



Utr 



FIG. 234B. HORIZONTAL SECTION THROUGH AN EMBRYO OF Lacerta agilis. 

 (After M. Braun.) 



Pep, peritoneal epithelium ; Sg.bl, segmental vesicles ; Uw t mesoblastic somites. 



(glomerulus) (M\ arising from the renal artery, which, lies within 

 an expanded portion of the tubule the Malpighian capsule, 

 the outer wall of which is pushed in to receive it ; (3) a coiled 

 glandular tubule (DS) ; and (4) a terminal portion (US), 

 connecting the latter with the segmental duct (SG). (Comp. 

 also Fig. 235.) 



