30 Marvels of Pond-Life. 



CHAPTER III. 



FEBRUARY. 



Visit to Hauipstead — Small ponds — Water-fleas — Water-beetle — Snails 

 — Polyps — Hydra viridis — The dipping-tube — A glass cell — The 

 Hydra and its prey — Chydorus sphsericus and Canthocamptus, or 

 friends and their escapes — Cothurnia — Polyp buds — Catching 

 Polyps — Mode of viewing them — Structure of Polyps — Sarcode — 

 Polyps stimulated by light — Are they conscious ? — Tentacles and 

 poison threads — Paramecium — Trachelius — Motions of Animalcules, 

 whether automatic or directed by a will — Their restless character. 



|T has been a bitterly cold night, and as the sun 

 shines on a clear keen morning, and glistens 

 in the hoar-frost which covers the trees, it 

 might seem an unpropitious time for visiting the ponds, 

 in search of microscopic prey. We will, however, 

 try our luck, and take a brisk trot to the top of 

 Hampstead Heath, where the air is still keener, and 

 the ice more thick. Arriving at the highest point, 

 London appears on one side enveloped in its usual 

 great coat of smoke, through which St. Paul's big 

 dome, with a score or two of towers and steeples, can 

 be dimly made out ; while looking towards Harrow-on- 

 the Hill, or Barnet, we see the advantage of country 

 air in the sharpness with which distant objects cut the 

 blue sky. We leave the large ponds for another time, 



