PHOLAS. 183 
anteriorly, the one giving filaments to the right, the other to 
the left palpum, from whence additional ramifications proceed 
to the anterior parts of the body, besides supplying the muscles 
of the foot. The posterior ganglion is situated between the 
heart and the anus, and is connected with the anterior one by 
two close, parallel, dorsal, very minute longitudinal threads 
that are seen without difficulty, and cannot well be mistaken 
for veins; the minor mass furnishes threads to the adductor 
muscle, and sends to the ovarium and muscles of the belly 
appropriate filaments. This is all that I have been able to 
observe of the nervous system, and collect from it, that how- 
ever insignificant the ganghonic masses may appear, their 
effects on the muscles prove that the potentiality of their in- 
fluences is not impaired by the mimuteness of the hair-like 
threads which are the conductors of the subtle fluid that 
excites their action. 
The Digestive Organs. 
We commence with the mouth, situate immediately above 
the connecting labium of the palpi; it is rather a large trans- 
verse orifice, and leads directly into the simple cesophagus, 
which proceeds with a portion of the liver on each side of it 
through the anterior part of the dorsal range into a small oval 
stomach, the base of which is enveloped by the light green 
granwar liver which pours the bile mto its rigid coat by 
several ducts ; its cavity is almost filled up with a folded plate, 
which I call the gizzard or stomachal attritor, and authors 
the tricuspid membrane, which is erroneously, as I think, 
considered by some malacologists an agent to regulate the 
entrance of the bile from the liver. I think this idea cannot 
be sustained, as besides the stomach being provided with bile 
ducts, one of the axes of the tricuspid corneous plate is fixed 
at the cardiac orifice of the stomach, and receives the animal- 
cule as they descend the cesophagus ; and after trituration by 
the gizzard, which is worked by the elastic hyaline stylet, they 
pass through the other axis of the tricuspid membrane, which 
is inserted in the pyloric orifice into the mtestme. I have 
preparations showing the gizzard im the stomach with its 
