BULLETIN OF THE BUREAU OF FISHERIES. 
439 
PLATE L. 
Fig. 20. Semidiagrammatic drawing of a specimen, ventral side up, to show the veins which enter 
the kidneys and those which emerge from them. The shell, part of theleft mantle, and the gills of the 
left side have been removed. One kidney is cut open to show that the large vein upon entering the 
kidney breaks up into capillaries. F, foot; G, gill; G / , the upper border of the reflexed lamella of the 
gill; K, kidney; O, osphradium; i, 2, and 3, mantle nerves from the visceral ganglion which lies upon 
the adductor muscle at the posterior end of the kidneys; 4, nerve to mantle gland; V, vein entering 
the kidney (the same as the vessel labeled V in fig. 19); x, the vessel which carries the blood from the 
kidney to the gills; y, the vessel which receives the blood from vessel x and distributes it to all parts 
of the gill. 
