136 Marvels of Pond-Life. 



towards it. The oesophagus terminates in a digestive 

 tube, like the trunk of a tree, from which numerous 

 branches spring. This arrangement is probably analo- 

 gous to that of the phlebenterous mollusks described by 

 Quatrefages, in which the ramifications of the stomach 

 answer the purpose of arteries, and convey the nutrient 

 fluid to various parts of the body. It is also likely 

 that they minister to the function of respiration. 



The cilia on the surface, which are arranged in 

 parallel lines, are best observed when the animal is 

 slightly flattened in a live-box ; but this process pro- 

 duces a considerable derangement in the relative position 

 of the internal parts, and they can only be well seen 

 when it is immersed in plenty of water, and is polite 

 enough to stand still, and submit his digestive economy 

 to a steady gaze. The only way to succeed in this 

 undertaking is to have a large stock of patience as well 

 as a convenient cell or trough. The table must be kept 

 steady, and the prisoner watched from time to time, 

 and at last he will be found ready for display. 



Pritchard says this animal, whose name is Trachelitis 

 ovum, is an inhabitant of stagnant bog water, and has 

 been found encysted. My specimens could not be 

 called plentiful, but for several weeks I could generally 

 find two or three, by filling a four-ounce vial from the 

 glass jar, and examining its contents with a pocket -lens. 

 If none were present, another dip was made, and usually 

 with success. 



One evening I caught a good specimen by means of 

 the dipping-tube, and cautiously let it out, accompanied 

 by a drop of water, on the glass floor of the live-box. 



