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 O3sophagus which descends into a small stomach, the 

 contents of which under the microscope appeared to be wood 

 reduced to a pulpy mass, that, after having undergone the 

 action of the gizzard, is discharged into the intestine, which, 

 as soon as it springs from the pylorus, mounts to the integu- 

 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 oesophagus 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 -iVths, when, by a sudden short turn, it 

 retraces its steps for f^ths of an inch, when it again turns and 

 makes an oblique reach of about | an inch ; it then makes 

 a further gyration, forming a complete but small sigmoid 

 flexure, and pursues its course for 1 inch -j^ths to the anterior 

 part of the body, which it descends, coasting for Wths 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 in unison with the 

 true mouth. I can conceive no other use for this valve than 

 to admit water to the mouth, oesophagus 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 



