192 EVENINGS AT THE MICROSCOPE. 



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 

 specimens of a much larger and liner species than the 

 common one, — the Belanus ])orcattis, 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 

 vour 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 withdrawn.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 on some one conveniently 

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

 moment, 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 apparatus 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 ratus is quickly withdrawn, and disappears beneath the 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 re-open : 

 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 shall 

 see what an exquisite piece of mechanism it is. The little 

 hand consists of twenty-four long fingers, of the most 

 delicate tenuity, each composed of a great number of 

 joints, and much resembling in this respect the antenna? of 

 a Beetle. These fingers surround the mouth, which is 

 placed at the bottom of the sort of imperfect funnel formed 



