384 EVENINGS AT THE MICROSCOPE 



You see here a jar, on the glass side of which are 

 traced a number of very fine white lines, barely discerni- 

 ble by the unassisted eye. But by the aid of the lens 

 you see that each line is a long and slender thread, which 

 creeps along the glass, and at length starts out from it free 

 for a short distance, and is then terminated by a long 

 club-shaped body, which carries at its extremity four hori- 

 zontally divergent organs, like the arms of a turnstile. 

 Tracing down the threads to their lower extremities, you 

 see that they are branches of one thread, which creeps 

 irregularly over a filamentous sea- weed growing from a 

 stone in the jar. The sea-weed had been in the vessel for 

 several weeks, and the water having been undisturbed, 

 the knobbed thread, which was originally confined to the 

 plant, continued to grow, and coming into contact with 

 the glass spread upon it. Many other threads have ex- 

 tended from the creeping root, some of which stand up 

 freely in the water, with their knobbed extremities float- 

 ing in the wave. 



This is one of the Polype tribe, named Stauridia pro- 

 ducta, and as its form and structure are interesting, we 

 will devote a few moments to its examination. We can 

 easily sever one or two of the freely floating threads, and 

 transfer the amputated portions to one of the live-boxes 

 of the microscope. The motions and appearance of the 

 club with its organs will be, for a while, little affected by 

 the violence. 



The long cylindrical thread is enveloped in a transpar- 

 ent horny tube, which, however, so closely invests it that 

 it is with difficulty distinguished. The club-shaped head, 

 or individual polype, is an enlargement of the thread, 

 which protrudes from the investing tube. It is swollen 



