214 ALTERNATION OF GENERATIONS. 



of oval gemmae or buds, appropriately so called by 

 most writers, which appear like minute jelly bubbles, 

 covered with numberless vibratile cilia. These 

 organs, ten thousand times more delicate, we may 

 imagine, than the eyelashes of some infant member of 

 fairy land, are ever in constant motion. The cur- 

 rents produced thereby serve to propel the little 

 animal to some stray pebble or stalk of sea-weed, 

 situated at a respectful distance from its gelatinous 

 relative. On some such object the young bud 

 attaches itself, and proceeds to vegetate. 



The body gradually lengthens, and becomes enlarged 

 at its upper extremity; from this portion of the 

 animal four arms appear surrounding a kind of 

 mouth. The arms lengthen, and are soon joined by 

 four others. These organs, as also the inner surface 

 of the lips and of the stomach, are covered with cilia, 

 and become highly sensitive. They are used in the 

 same manner- as the tentacula of the Actiniae, namely, 

 for the capture of food. There is this difference, be 

 it observed, between the two animals, that while the 

 infant Medusae labours incessantly to gain its daily 

 meals, the zoophyte remains still, and trusts to chance 

 for every meal that it enjoys. 



Fresh sets of arms continue to be developed suc- 

 cessively upon the little jelly fish, until the whole 

 amount in number to .twenty-five or thirty. ' And the 

 body, originally about the size of a grain of sand, be- 

 comes a line, or the twelfth part of an inch in length/ 



