232 PROCEEDINGS OF THE ACADEMY OP [1883. 



connection "between the cells of the infundibulum and the ganglion 

 cells, although one undoubtedly exists. 



The nerve which connects tliese two ganglia consists of parallel 

 fibres which are connected with the poles of the ganglion cells. It 

 takes little or no color with picro-earmine, and is quite pale when 

 compared with the surrounding tissues. 



The posterior and smaller of these two ganglia I am inclined to 

 believe is the supra-intestinal ganglion, which, according to 

 Spengel,^ lies in connection with the ganglion olfactorium. It is 

 about one-half the size of this latter ganglion, and lies in the 

 same plane with it, so that a horizontal section through one takes 

 in the other. On one side it lies in contact with the anterior wall 

 of the pericardium ; on tiie other it touches the internal portion of 

 the same part of the kidney which touches the internal portion of 

 the gnnglion olfactorium. 



This ganglion receives a branch from the body, which is the one 

 probably connecting it with the a?sophageal ring. It sends also a 

 branch posteriori^'. 



The form and structure of this ganglion are similar to that of 

 the ganglion olfactorium, save that there is no funnel-like invagina- 

 tion. This ganglion has all the points that characterize the supra- 

 intestinal ganglion : first, a branch which connects it with the 

 pleural or visceral ganglion ; secondly, a branch that connects it 

 with the abdominal ganglion, and thirdly, a connection with the 

 ganglion olfactorium. 



The tentacular ganglia. — Besides the ganglia already described 

 as belonging to the central nervous system, together with the 

 ganglion olfactorium, there is a pair of ganglia which do not 

 belong to the central nervous system proper, and may be con- 

 sidered as belpnging to the peripheral nervous system. These 

 ganglia have already been pointed out by P. B. iSarasin,^ as 

 existing in the fresh-water Pulmonata. Sarasin agrees with 

 Lacaze-Duthiers,^ that this pair of ganglia are homologous to 

 those found in the end of the tentacles of Helix. They are situ- 

 ated behind the position of the eye, and in close contact with the 



* D. Gcruchsorg. u. d. Nervensyst. d. Moll., etc. 



* Drei Sinnesorgaue und die Fussdiiise eiiiiger Gastmpoden. Arbeit 

 aus dem Zool. Zootoin. Instit. zu Wiirzburg, Bd. vi, 1883. 



^ Die Syst. Nerv. d. Moll, gast., etc. 



