178 THIRTY-FIFTH REPORT ON THE STATE MUSEUM. 
tory apparatus. The lining of the mouth consists of ciliated epi- 
thelium cells, continuous with the labial palpi, or, as they are desig- 
nated by some authors, the oral tentacles. The mouth connects with 
the stomach by a very short esophagus, the lining of which also con- 
sists of ciliated epithelium, the food being conveyed to the stomach by 
the action of the cilia. 
The stomach (Pl. 6, s.), which is situated just back of the anterior 
adductor muscle, is irregular in shape, the general form being round 
or oval, with several depressions and plications which are stronger 
on the inner surface. The stomach is invested by the liver (Pl. 6, 1.), 
with which organ it is connected by the minute orifices in the 
cecal tubes of the liver. On the right side, the stomach communi- 
cates with a blind sac, the nature and use of which body is not defi- 
nitely known. It varies in size at different times of the year, being 
found most prominent after winter. Various explanations and con- 
jectures have been made regarding the use of this organ, but nothing 
is known with certainty. The general direction of the esophagus and 
stomach is toward the dorsal margin. 
The intestine proceeds from the left side of the stomach ; as soon as 
it leaves the stomach it turns downward at an angle of a little more 
than 45 degrees to the hinge-line (PI. 6, fig. 1, i. ¢.). 
The measurements given below are from a specimen, the body and 
foot of which combined are five centimetres in length and three in 
width ; of course in larger and smaller specimens, the individual 
measurements would be different, but the comparative measurements 
would be the same. 
The intestine proceeds from the stomach downward and backward 
with a slight curvature till within a short distance of the posterior 
margin of the body, a little above the foot ; it then turns toward the 
dorsal side for a short distance, corresponding in curvature to 
the margin of the body. At about midway between the dorsal 
and ventral margins of the body (that is, the body proper and the 
foot), the curvature is toward the anterior and so continues to a point 
five millimetres below the renal organ, and a. little less than two centi- 
metres posteriorly to the stomach — for this distance the intestine is 
small, being about one millimetre in diameter. At this point 
the dorsal part of the intestine is slightly prolonged and firmly at- 
tached to the surrounding mass (PI. 6, fig. 1, i. é.). The intestine 
here turns abruptly toward the right side and continues in that direc- 
tion for the distance of three millimetres, then turning backward 
and continuing just posterior to and nearly parallel with that portion 
previously described to a point about two-fifths the length of the body 
from the mouth, where the ventral portion is slightly prolonged and 
