witK a revision of thè Limnceidce of Authors. 337 
Two branehes extend from tbe npper ganglioii to thè vicinitj 
of thè heart, where another minute pair of ganglia was cletected. 
From eac'h of tliese a single nerve, which afterward divides, 
proeeeds in a posterior direction. 
Alimentary System. The oesophagus leaves thè buccal mass 
with two sudden liexures ; it then becomes slightly dilated and 
proeeeds, curving with thè shell, to thè first half of thè apical 
■whorl. Here it turns sharply on itself, thè reflected portion 
passing underneath thè other, and, passing tlie posterior end, 
enters thè anterior end of thè stomach. The latter is ovoid, 
stronglj muscular, and recalls in appearance thè gizzard of a 
fowh It is divided, apparently, into three indistinct regions, 
of which thè two outer are really muscular fibre and thè inner 
regiou is thè cavity of thè stomach. 1 found it full of commi- 
nuted vegetable matter, araong which were many small grains 
of sand. Whether these are merely accidental. or serve thepur- 
pose of triturating thè food, there are no means of determining. 
The intestine leaves thè stomach at thè posterior end, and 
passes beneath it, forward, without any marked flexure. follow- 
ing thè curve of thè spire and opening on thè left side of thè 
neck, just within thè mantle cavity and dose to thè opening 
of thè vagina. 
A gland of a yellowish color, emptied by a duct which passes 
into thè throat, was supposed to be a salivary gland. 
The liver is of a greenish brown bue, and extends nearly to 
thè apex of thè spire. It is of no definite shape, but fills thè 
cavities between thè lobes of thè ovary and those in thè regiou 
of thè stomach ; and is bounded, anteriorly, by thè wall of thè 
pulmonary chamber. It is well supplied with blood-vessels 
which ramify in every direction. The buccal piate is some- 
what cordiform or rounded triangular. It is smooth and of a 
yellowish horn-color, but thè cutting edge is slightly thicker 
than thè rest. A blunted rounded point forms thè centre of thè 
cutting edge, which is simple and without notches or strife. 
There are no accessory plates. 
