UROGENITAL SYSTEM. 



309 



stome; the cilia, which may continue for some distance along the 

 inside of the tubule, serving to create a current which carries the 

 ccelomic fluid into the tubule and thence outward. Farther along 

 the tubule expands into a Malpighian or renal corpuscle (fig. 315). 

 This consists of a vesicle (Bowman's capsule), one side of which 



FIG. 314. Diagram of conventionalized excretory tubule. a, ascending limb of 

 Henle's loop; b, Bowman's capsule of Malpighian body; c 1 c 2 , first and second con- 

 voluted tubules; ct, collecting tubule; d, descending limb of Henle's loop; g, glomerulus 

 of Malpighian body; with artery and vein; h, Henle's loop; n, nephrostome opening into 

 ccelom; x, entrance of other tubules into collecting duct. 



projects into the other, nearly filling the cavity. This inturned portion 

 is the glomerulus. It consists of a network of capillary blood-vessels, 

 supplied by an artery and drained by a vein. Beyond the connexion 

 of the Malpighian body the tubule becomes contorted or convoluted 

 and its cells are strongly glandular in character. This first convoluted 

 tubule is succeeded by a nearly straight tract, folded once on itself into 



FIG. 315. Diagram of renal (Malpighian) corpuscle, a, artery; b, Bowman's capsule; 

 gl, glomerulus; n, nephrostome; /, nephridial tubule; v, vein. 



the descending and ascending limbs of Henle's loop. Next follows 

 the second convoluted tubule, which passes by means of a short 

 connecting tubule into a non-glandular collecting tubule into which 

 several other systems of excretory tubules enter, and which leads 

 more or less directly into the urinary duct which conveys the waste 

 from the excretory organ to the exterior. 



