Haswell's Text-Book of Zoology, page 648, the reverse loop of 

 the intestine in the posterior portion of the visceral mass is not 

 given. This may not be present in the species figured, but it 

 seems quite possible that it might have been overlooked in dis- 

 sections as the backward turn is so abrupt and takes place so 

 near the other portion of the intestine. After running dorsally 

 nearly to the hinge line, the intestine bends rather abruptly pos- 

 tero-ventrally, perforates the ventricle of the heart, and termi- 

 nates posterior to the adductor muscle. The last inch or more 

 of the intestine protrudes from the general body and ends in a 

 dorsal turn that directs the faeces toward the edge of the shell in 

 the same direction that is taken by the excurrent stream of water 

 that is coming from the gills. It is important that the faeces 

 should be voided, as they are, where they may be promptly 

 rernoved by the current of water coming from the gills. 



Throughout the length of the alimentary canal its epithelium 

 is ciliated and movements of its contents are dependent upon the 

 action of the cilia. The general movements caused by the 

 muscles of the body wall may have some effect, but there is no 

 special muscular provision to aid in the movement of ingested 

 material. 



The muscles covering the pericardium are continued down 

 over the otherwise free extremity of the intestine and may have 

 the action of a sphincter but in the living individuals and in the 

 sections examined, the lumen of the intestine seems to be quite 

 as unobstructed in this region as in other regions. 



LABIAL PALPS. 



These organs are essentially lips and have for their chief, if 

 not their only, function the conducting of food into the mouth. 

 There is as in other forms a pair of palps on each side of the 

 body. The palps on one side of the body are connected with 

 those of the other above and below the mouth so they resemble 

 large drawn out lips with the upper lip of each side covering the 

 under lip of the corresponding side so their inner surfaces, that 

 is the surfaces continuous with the epithenium of the oesophagus, 

 are applied to each other. In many kinds of lamellibranchs the 

 palps consist of inconspicuous smooth flaps of tissue that have 

 their inner or opposed surfaces thrown into series of ridges and 



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