42 WALTER K. FISHER, 



Opposite this from the posterior end of each ganglion there also de- 

 parts a much more prominent, though delicate nerve, which passes 

 around the hind end of the subradular pouch, and then proceeds for- 

 ward. Almost at once each divides into three branches, as shown by 

 Fig. 38. The outermost ones turn directly at right angles and pro- 

 ceed outward over the dorsal wall of the pouch. The others {Sub. R. N) 

 go forward and anastomose, branch, and form a delicate network over 

 the whole sublingual (or subradular) organ, and anterior portion of 

 the dorsal wall of the subradular pouch. These nerves can be made 

 out only in a carefully macerated specimen, as they are extremely 

 delicate. Their position seems to be in a thin connective tissue basis, 

 beneath the epithelium. 



From the subradular commissure a long slender nerve {Ppn') is 

 given off on each side, forward to the palps, and can be traced as 

 far as indicated in the figure. Another very tiny nerve is given off 

 to the subradular pouch from the point where the commissure turns 

 forward. From this point also, as already indicated, a long nerve {bn) 

 passes backward ;in the radula protractors to the hind end of the 

 buccal mass, whence it proceeds to the sublingual artery and becomes 

 too small to follow further. From this nerve, about half way from its 

 origin to the end of the buccal mass, two other nerves are given off 

 into the heavy muscles. One {bn') passes forward above the sub- 

 radular. pouch (innervating the forward portion of the radula pro- 

 tractors) and the outer {bn") goes forward and outward. I am un- 

 aware of the final distribution. 



The subradular ganglia were also found in Acmaea patina and the 

 main connections and nerves followed out. These were identical with 

 those of Lottia gigantea. I have no hesitation in saying that the 

 ganglia are characteristic of the Acmaeidm in general. The theoretical 

 bearings of the presence of these ganglia on the relationships of the 

 Docoglossa are most important and it would be entirely superfluous 

 to detail them in this connection. 



Pedal ganglia and nerves (Figs. 30 and 33). The pedal 

 ganglia are the largest in the animal, and consist essentially of an 

 anterior thickened portion on each side, two long pedal cords, and 

 three distinct commissures {Pc, Pc' Pc"). The pedal cords {Ped. G') 

 are really elongated ganglia. In front, the main thickened pedal 

 ganglia {Ped. G) are connected by a heavy commissure {Pc), in which 

 are numerous ganglion cells. The cerebral and pleural connectives 

 enter each ganglion on the anterior face, which is produced forward 



