NO. 7. 



THE FARMERS' CABINET. 



109 



Microscope. — Polypi. 



The different species of sponge, which the 

 Microscope has discovered ,to be the habita- 

 tions of Polypi, are very interesting^ objects; 

 when viewed with an instrument of a moder- 

 ate power, they present to the eye a curious 

 mass of net-work, which once formed the 

 cells of the Polypus. If the power is in- 

 creased, the remains of the little tenants may 

 sometimes be detected. These consist of a 

 small bony or chalky axis, like a needle, 

 which, when the animal was living, formed 

 the centre of its body. 



There is a small species of sponge found 

 frequently among seaweeds, from its ap- 

 pearance called '* Crumb-of-bread sponge," 

 which, when placed under the magnifier, 

 seems to be almost entirely composed of 

 bunches of little needles, lying across each 



other like little net-work. B is a magnified 

 representation of a small piece of this 

 species. When dry, the little needles, 

 or spiculae, are so exlrenu'ly fine and sharp,^ 

 as to cause a most irritating itching, if un- 

 luckily they should get between the fingers- 

 of the observer. 



The animal of the CnralUnff!, which are 

 found so abundantly on every coast, attached 

 to stones and other substances, belong to the 

 same class, and the houses they construct 

 are excellent objects for the microscope. 



The annexed cuts are representations of 

 five difl'erent species, engraved of the natural 

 size, and accompanied by a portion consid- 

 erably magnified. 



In figures 18, 19, and 20, the Polypi them- 

 selves are seen, with their feelers put forth- 

 in search of prey. 



Fig. 16. 



Fii. 17. 



Fig. 18. 



Fig. 18. Sertulariapumila, Great tooth-coralline, 



19. 

 20. 



21. 



22. 



• potyzonias, Sea-tamarisk. 



— halecyna, Herring- bone cor- 



alline. 



— antfunina. Lobster's horn co- 

 ralline. 



— lendlgera, Nit coralline. 



Fig. 23 represents a magnified view of the 

 Hydra brunnea, or brown Hydra, another 

 species of Polypus, which is not uncommon I 



Fig. 



in fresh water in the months of July and 

 August. The cut shows the manner in which 

 the young are produced. These Polypi have 

 been the subjects of many curious experi- 

 ments, which show the surprising tenacity 

 of life in the lower order of animals. They 

 have been cut across, divided lengthwise, and 

 even turned inside out, and yet each portion 

 has not only continued living, but has become^ 

 a perfect animal. 



Fig. 21. 



Sea-weed and other substances,which have 

 been left for some time undisturbed, are fre- 

 quently found covered with a chalky in- 

 crastation, which appears to the naked eye 



like net-work, but, if placed under a moderate' 

 power, exhibits a series of little cells or 

 chambers, most beautifully formed : each 

 of these tiny nests originally contained a. 



