512 NATURE'S TEACHINGS. 



was long thought to be a separate creature, and was known 

 under the scientific name of Strobila. Modern researches have, 

 however, made the discovery that it is one of the transitional 

 stages between the creature known as the Trumpet-hydra 

 (Hydra tuba) and the Medusa, popularly known as Jelly-fish. 



The former almost exactly resembles the Hydra of our fresh 

 waters. It is a tiny transparent gelatinous bag so transparent 

 as to be scarcely perceptible, and with some thirty or forty 

 long and delicate tentacles hanging from its open end. These 

 tentacles are used in catching the minute creatures on which it 

 feeds. It is fixed, and, to use Mr. Rymer Jones's simile, looks 

 like a beautiful silk-like pencil waving amidst the water. Its 

 length is not quite half an inch. 



That it should be identical with the remarkable form shown 



TBUHPET-RTDBA. SALAD-DRESSING BOTTLB. 



in the illustration seems impossible, but such is the case. Its 

 body becomes contracted as if tied with strings, and every 

 segment thus formed develops a set of tentacles, breaks away, 

 and swims off in the form of a Medusa. The upper segment is 

 exhibited as undergoing this process. 



The figure is magnified so as to show the structure better, 

 its right length being about one-third of an inch. A full and 

 graphic history of this creature and its manifold changes may 

 be found in Mr. Kymer Jones's " Aquarian Naturalist." 



It is not likely that the inventor of the Salad-dressing Bottle 

 ever saw a Hydra, but the resemblance is strangely exact. 



