1916.] NATURAL SCIENCES OF PHILADELPHIA. 481 



as the overh iug right pleural ganglion, to which it is attached by a 

 short connective, thus producing a dextral zygoneury, while a 

 somewhat larger connective, passing ventral to the pharynx, unites 

 it with the left pleural ganglion. The supra-intestinal ganglion is 

 a fusiform mass united by a short connective to the right pleural. 

 The visceral ganglion, in contact with the ventral floor of the mantle 

 cavity on the right side of the body, is joined by connectives passing 



Fig. 1. — Dorsal view'of the nervous system <>( Crepidula adunca. The pedal 

 nerves are represented by broken lines; the right posterior pedal nerve is 

 omitted, p., penis; t., testis. 



