THE KIDNEYS 



91 



D. The Kidneys. 



The kidneys, or ' organs of Bojanus,' are paired, and lie 

 side by side just beneath the pericardium. 



K R U CO UO 



SC LM 



Fig. 27. — Anodonta cygnea. Diagrammatic view from the right side. 

 The right valve of the shell, the right mantle-lobe, the right giUs, 

 and the right auricle, have been removed. The alimentary canal 

 has been laid open from the right side as far as the point where it 

 enters the pericardial cavity. The pericardial cavity, the ventricle, 

 and the right kidney and ureter have been laid open from the right 

 side. The longer,arrow passes from the pericardial cavity through 

 the right reno-pericardial aperture into the right kidney. The 

 shorter arrow passes through the external aperture of the right 

 ureter, (a. m. m.) 



A, margiu of the left valve of the shell in which the animal is lying. A A, 

 anterior adductor muscle. AN, anus. B, ligament of the shell. SD, bile- 

 duct. BD', openijigs of bile-ducts into stomach. C, cloacal cavity. D, sep- 

 tum between the cloacal and branchial cavities. S, tentacles bordering 

 inhalent aperture. F, foot. Gr, line of fusion of inner lamellee of right and 

 left inner gills. GO, genital aperture. H, anterior aorta. I, intestine. K, 

 kidney. L, liver. LG, inner gill of left side. XjM, left mantle-lobe. M, 

 mouth. M", posterior aorta. O, cesophagus. PA, posterior adductor muscle. 

 PC, pericardial cavity. PR, right posterior retractor muscle. E, rectum. 

 BG, genital gland— ovary or testis. BM, line of attachment of right lobe of 

 mantle. BP, right reno-pericardial aperture. S, stomach. SC, median 

 supra-brfincliial canal, lying above the inner-gills. T, typhlosole. U, right 

 ureter. UO, extern^ opening of right ureter. V, cavity of ventricle. 



