92 POPULAE ILLUSTRATIONS OF 



and the coecal appendages (e). It has the power of contracting and 

 dilating its crest, and can turn over or perform somersaults on the 

 surface of the sea, but when adult it has not, as far as is known, the 

 power of guiding itself or sinking to the bottom. 



In 1862, Mr. Tudor, writing to the Times, stated that a consider- 

 able number of " Portuguese men-of-war " had been that summer 

 washed on to the shores of the Dorsetshire coast, and he remarked 

 that, as an old sailor, he never remembered seeing them before north 

 of 48 lat., and then only in the Gulf Stream. Mr. Tudor thought 

 that the appearance of these tropical creatures on our shores 

 indicated some extraordinary change in the course of the Gulf Stream. 



For more minute points connected with the economy of the 

 Physalia and there are many very interesting I must refer the 

 reader to the complete and clear description and illustrations of 

 Professor Huxley, in his " Oceanic Hydrozoa," published by the Bay 

 Society. 



The Physophoridae are divided into seven different families, most 

 of them consisting, as far as is at present known, of single genera. 

 They are all most interesting subjects of study to the naturalist, 

 but do not come within the scope of this work. 



The next order of the Hydrozoa comprises a large and most 

 interesting class of animals viz., the Medusidae, or so-called " jelly 

 fish " of our sea-shores. 



CHAPTER IV. 

 THE 



THERE is something very elegant and graceful in the glistening 

 Medusa as it rolls through the clearer waters of the sea in a 

 hot still day in July. The marvellous transparency of the creature, 

 as it bobs up and down by the side of the boat, renders it all 

 but invisible to the eye of the observer. But, fixing his attention 

 upon some coloured radiating markings, he will gradually realise the 

 fact that he is looking upon a semi-globular living thing, with a 

 central body and several tentaculee dependent from its rim. If, 

 again, the observer goes on to the shore at night, or sails along the 

 warm coasts of Italy, he may see hundreds of thousands of bright 

 sparks of light, or it may be balls of fire as large as small oranges, 

 moving through the water. In the day observation the weather 

 must be still and calm ; for his nocturnal visit, the sea should be 



