SEA- SIDE STUDIES. 



319 



stance is jelly-like, and their body is traversed by tubes which radiate 

 from the centre to the circumference. 



The sunfish, and all the disk-shaped jelly-fishes especially, are re- 

 markable for their stinging properties. When they come in contact 



Fig. 16. Scyphistoma of 

 Aurelia flavidula (Per. 

 &LeS). Magnified about 

 seven diameters. 



Fig. 17. Strobila of 

 Aurelia flavidula 

 (Per. & LeS). Mag- 

 nified about seven 

 diameters. 



Fig. 18. Strobila ot Aurelia flavidula 

 (Per. & LeS). Magnified fifteen diame- 

 ters. 



with the flesh of the bather, they cause a stinging sensation, similar to 

 that produced by nettles. This is why they are called sea-nettles, and 

 why in scientific books they are called Acalephce. 



Toward the close of summer the sunfish lays numerous eggs, and 

 in the autumn it perishes. The eggs hatch into little oval bodies, 



& 



Fig. 19. Sunfish (Aurelia flavidula, Per. & LeS). 



Offspring of Figs. 16-18. 



which swim freely about by means of minute hair-like appendages. 

 After a time each one of these free-moving bodies attaches itself to a 

 rock, shell, or sea-weed, and takes the form of a plant, and is then 

 called scyphistoma (Fig. 16). As this goes on growing, it soon begins 

 to divide into segments by horizontal constructions. By this process 

 our little scyphistoma becomes a strobila (Figs. 17, 18). By continued 



