98 THE STORY OF LIFE IN THE SEA.S. 



found at or near the surface of the seas 

 of all climes. Some of them possess great 

 floats like Physalia and Velella, but the majority 

 of them have either no floats at all or such as are 

 too small to do more than assist in keeping the 

 animal near the surface. All of these Siphono- 

 phores are provided with little bells, which, con- 

 tracting rhythmically like a Jelly-fish, drag the 

 animal along, sometimes to the surface, sometimes 

 a few fathoms below it. Some of these forms are 

 extremely graceful, being like long strings of 

 jelly, with numerous clusters of Polyps and long 

 feathery tentacles, towed through the water by 

 one or two exquisitely delicate little bells situated 

 at the leading end of the string. 



A few words must now be said about the Salps, 

 because in some seas the water is on occasions so 

 full of them that they seem to be packed together 

 ready for preserving. The simplest form of Salp 

 is like a small sac or barrel of transparent gela- 

 tinous substance open at both ends. Eunning 

 round the barrel are five or seven bands of a less 

 transparent nature, appearing to the unaided 

 vision like milky white streaks. These streaks 

 are bands of muscles by which the movement of 

 the body through the water is assisted. Some- 

 times they are seen swimming about independ- 

 ently of one another, sometimes Salps very similar 

 to them in general appearance are seen to be 

 attached to one another in long chains. At first 

 it was supposed by naturalists that the former or 

 Solitary Salps were of a different species to the 

 latter, or Chain-salps as they are called; but it 

 has been discovered that these two forms are but 



