74 



the branchial heart of its side. This slanting course at 

 first causes them to run external to the kidneys, but more 

 posteriorly they run over the kidney sac (fig. 69), and 

 then passing between the ureter and the oviduct — or 

 penis they p-ain the branchial heart, and finally end in 

 the branchial nerve which runs itp the fleshy axis of the 

 pfill (fig. 69, Bl ' . N.). The visceral nerve swells during its 

 course into two ganglia, of which the second is the larger. 

 The first is a small oval ganglion, just anterior to the 

 ureter. From it radiate hue nerves to the oviduct, 

 coelomic canal, flask-like division of the coelom, and the 

 aorta (fig. 69, (/'). Two other fine nerves are given off, 

 one running down the surface of the kidney to the wall of 

 the genital capsule, while the outer and smaller nerve ends 

 in the kidney wall (fig. 09). The second ganglion is 

 larger, and is about 3 mm. across (fig. 69, ;/"). It is 

 attached to the cord dorsally, and adheres to the wall of 

 the branchial heart. Branches radiate out from its free 

 edge, to the Avails of the lateral venae cavae, and the 

 efferent artery. Several branches are also given off to the 

 substance of the branchial heart, and there is a small 

 anterior branch which runs to the muscles of the back. 

 Two longer blanches sink down dorsal to the kidney, and 

 end in the back and the genital capsule respectively. 

 Beyond this ganglion the nerve may be called the 

 branchial nerve. It runs along that side of the gill 

 nearest to the visceral mass, just lateral to the afferent, 

 blood vessel (fig. (i ( ), HI. 2V.). It gradually narrows down 

 with the decreasing size of the gill, and swells to a 

 ganglion at the level of each internal lamella of this organ 

 (tip. li!), HI. (/.). Each ganglion gives off a nerve which 

 runs down the gill lamella to which it corresponds, and 

 also a second nerve which runs dorsal to the afferent 

 vessel, and so reaching the external side of the gill feeds 



