222 EVENINGS AT THE MICROSCOPE 



more intimate acquaintance with the little builders at 

 leisure. 



These are Barnacles (Balanidce). Such a colony I have 

 now in my possession, which I will submit to you, for 

 they present a beautiful and highly interesting spectacle, 

 when engaged in their ordinary employment of fishing for 

 a subsistence. And not only so, but I have living speci- 

 mens of a much larger and finer species than the common 

 one the Balanus porcatus, whose castle stands an inch or 

 more in height. The structure, however, and habits are 

 pretty much the same in both. 



"Without disturbing the busy fishers, then, just take 

 your seat in front of this tank, and with a lens before 

 your eye watch the colony which is seated on that piece 

 of stone, close to the glass side. From one and another, 

 every instant, a delicate hand is thrust forth, and presently 

 withdrawn. Fix your attention OD some one conveniently 

 placed for observation. It is now closed; but in a mo- 

 ment a slit opens in the valves within the general orifice, 

 displaying a black lining with pale blue edges; it widens 

 to an oval; the pointed valves are projected, and an ap- 

 paratus of delicate curled filaments is thrust quickly out, 

 expanding and uncurling as it comes, to the form of a 

 fan; then in an instant more the tips of all the threads 

 again curl up, the threads collapse, and the whole appa- 

 ratus is quickly withdrawn, and disappears beneath the 

 closing valves. The next moment, however, they reopen, 

 and the little hand of delicate fingers makes another grasp, 

 and so the process is continually repeated while this season 

 of activity endures. 



Now, by putting this specimen into a glass trough, 

 and placing it under a low power of the microscope, we 



