Voracity of the Asplanchna, and its Stomach Currents. 183 



may be roughly compared to a long omnibus cushion with 

 rounded ends. It is capable of much motion, and some apparent 

 change of form. I have just mentioned what I may call its normal 

 position ; but in a sketch before me, the stomach has ascended 

 quite above it, and below it lies a large, rough, resting egg, 

 nearly ready for expulsion.* Situated a little above the orifice 

 from which the eggs or young are discharged, is the contractile 

 vesicle, or heart, whose motions are easily seen when the other 

 life apparatus is out of the way. There are also complicated 

 tubes, which under favourable circumstances exhibit the so- 

 called " tremulous bodies" — little finger-like projections, on 

 which a high power detects ciliary action that has been sup- 

 posed to be connected with the animal's respiration. 



It is a most voracious creature, and its stomach is often a 

 natural history museum. The teeth do not damage the objects 

 as they go down, so that in one of my specimens I found a 

 small volvox apparently uninjured, and waiting the slow opera- 

 tion of the digestive juice. Mr. Gosse also mentions an 

 instance in which a rotifer that had been passed into the 

 stomach escaped alive. In the stomach of another asplanchna, 

 of which a drawing was made, were no less than seven small 

 rotifers and the jaw of an eighth, one arcella, and a quantity of 

 imperfectly crystallized transparent particles, that acted upon 

 polarized light, and may have been uric acid, together with a 

 mass of matter too much digested to determine its origin. The 

 asplanchna is not only willing to swallow any number of her 

 fellow- creatures, animal or vegetable, that her stomach can 

 possibly hold, but she gulps down objects apparently as 

 inconvenient as if a man should swallow a rolling pin, or the 

 kitchen poker itself. When such an awkward article has 

 been bolted, the stomach is widely distended ; the crop does 

 its part to make room for the visitor, by pursuing the same 

 course, and the result is that the entire digestive passage, and 

 stomach bag, together take a triangular form. I saw several 

 instances of this curious process. In one a — relatively — very 

 large piece of the tracheal tube of some insect was stretched 

 like a beam across the stomach, which it pushed quite out of 

 shape-. In another case, the creature had swallowed that 

 beautiful little lively vegetable, the Euglena pyrum, and the 

 memorandum I made on the occasion was as follows : — " 2nd 

 Dec, 1863. Asplanchna^B, young one,had swallowed aaEuglena 

 pyrum, which at one time came partly up into the oesophagus, 

 stretching it so that it was difficult to tell where the stomach 

 began. Then it arranged itself crosswise at the bottom of the 

 stomach, and the oesophagus, crop, and stomach were stretched 



* The ordinary eggs are hatched inside. I saw several young ones ex- 

 truded, exactly resembling the mother. 



