TEREDO. 219 
The mouth is a triangular V-shaped aperture placed imme- 
diately above the foot; on each side there is a palpar or 
salivary mass, which from its wavy streamlets appears to be of 
the latter quality; they have a glandular aspect, and may 
perhaps combine tentacular uses. The mouth opens into a 
short cesophagus which descends into a small stomach, the 
contents of which under the microscope appeared to be wood 
reduced to a pulpy mass, that, after havmg undergone the 
action of the gizzard, is discharged into the imtestine, which, 
as soon as it springs from the pylorus, mounts to the imtegu- 
ments that divide the dorsal aperture from the peritoneal 
cavity, passing through them and showing from without a 
tubular inflation that has been mistaken for the cesophagus of 
the second stomach, but is undoubtedly an intestine, which I 
have traced and opened throughout its length. It proceeds in 
a straight line through the liver to about the centre of the 
ovarium for 1 inch =%,ths, when, by a sudden short turn, it 
retraces its steps for °,ths of an inch, when it again turns and 
makes an oblique reach of about 4 an inch; it then makes 
a further gyration, forming a complete but small sigmoid 
flexure, and pursues its course for 1 inch ;8,ths to the anterior 
part of the body, which it descends, coasting for ;®,ths of an 
inch the foot to the external pyloric point of the stomach, and, 
becoming a short rectum, opens into the tubular mantellar canal 
at some distance from the anal siphon; the whole of the cir- 
cumvolution is about 5 inches, far exceeding that of the Pho- 
lades. The valvular dorsal flap before mentioned covers the 
aperture under it, assisted by a fine membrane perforated to 
correspond with the oval aperture, which appears to be in aid 
of the external valve for preventing the ingress or egress of 
water, except at the minute perforation m unison with the 
true mouth. I can conceive no other use for this valve than 
to admit water to the mouth, cesophagus and stomach when 
the foot is engaged in excavation, and in consequence perhaps 
the anterior gape is hermetically closed. 
It would appear that the animal swallows the excavated 
wood, and does not eject it by currents of water. I infer this, 
as not only the stomach but the intestine is always filled with 
