TETHYS DACTYLOMELA (RANG) 33 



three main branches, is distributed to the vesicle of Swammerdam 

 and its duct. 



The second (/. v. ^), is a strong, flattened nerve from the 

 posterior right side of the gangUon. It passes backward along 

 the body wall, giving off a branch to the liver, another to the large 

 hermaphroditic duct, a third which soon bifurcates, one sub- 

 division being distributed to the dorsal peritoneum and muscles, 

 the other, recurving forward, gives off a number of delicate 

 branches to the dorsal peritoneum and muscles, and itself anasto- 

 moses with a branch of the third right pedal nerve, the united 

 nerves sending a branch to the posterior face of the Organ of 

 Bohadsch. The main trunk of the nerve continues backward, 

 penetrates the dorsal body wall, and bifurcates to the anal por- 

 tion of the alimentary canal and to the walls of the siphon. 



Close to the left of the second nerve arises an equally strong 

 nerve, very soon dividing into two main trunks, which pass 

 backward, diverging from each other. In the largest specimen 

 these two trunks arose as separate nerves from the ganglion. 

 The left one (/. v. ja), of these sends a branch to the liver, a 

 more slender one to the muscles of the dorsal body wall, while 

 the main trunk curves upward around the posterior wall of the 

 pericardium, and thence forward in its dorsal wall, and is dis- 

 tributed to the heart and the kidney. The right main branch 

 (/. V. j&), of the third nerve sends a branch to the liver, another 

 to the large hermaphroditic duct, and, crossing the base of the 

 adnexed genital mass, gives off a branch to the small genital 

 ganglion lying upon it. Crossing the small hermaphroditic duct, 

 it gives off two branches to it, and, continuing backward, finally 

 terminates among the muscles in front of the posterior portion of 

 the alimentary canal. 



Parietal nerves. From the right, or parietal ganglion arise 

 two nerves. A short distance behind the junction of the pleuro- 

 parietal connective with the anterior end of the parietal ganglion 

 the first nerve {r. p. i),\s given off. It is a small trunk, sending 

 a number of branches to the region of the genital opening, while 

 another branch (/a), courses forward and unites with a branch of 

 the third pedal nerve, thus forming a parieto-pedal connective. 

 In one individual the branch of the third pedal nerve continued 

 on to unite directly with the parietal ganglion, close to the entrance 



