The Swan-Mussel and Us Anatomy. 



69 



oblong form, and furnished exteriorly with a ciliated epi- 

 thelium, the action of which may be readily seen under a low 

 magnifying lens. Many authors have supposed that these 

 ciliated processes have something to do with the respiration ; 

 their more immediate office, however, is to bring particles of 

 food within the reach of the mouth. There does not appear to 

 be any oesophagus in the Anodonta, the mouth opening imme- 

 diately into the stomach, whose internal coat consists of the 

 most delicate lace-like structure -, in form it is roundish, and is 

 made up of several smaller depressions, the biliary cripts of 

 comparative anatomists. The liver, a large organ occupying a 

 considerable portion of the anterior extremity of the animal, 

 readily recognized by its brownish green colour, consists of a 

 number of coeca arranged in racemose clusters, which pour 



Fig. 1. 



A. Crystalline style of Anodonta (natural size). 



B. Portion of ditto magnified, showing extremely minute animalcules im- 

 bedded in its gelatinous substance. 



C. Filiform animalcules, x 400 diam. 



their secreted fluid into the stomach and part of the intestine 

 by a number of very minute pores, according to the opinion of 

 the French anatomist * whose anatomical investigations of the 

 molluscs are worthy of the highest consideration. Projecting 

 within the stomach in the Anodonta and TJnio, is a very curious 

 organ whose function has been hitherto unexplained. If you 



* M. Moquin-Tandon, one of the best of living comparative anatomists. 



