10 CLASSIFICATION. 



addition of a little iodine to the drop in which they 

 swim, it is found that four specimens in the little 

 group before us, namely, the Volvox (Fig. 2, 2), the 

 Polytoma (Fig. 2, a), the Navicula (Fig. 2, 5), and the 

 Pandorina (Fig. 2, 11), at once turn blue, indicative 

 that they contain starch, a substance thought to be 

 peculiar to the vegetable creation, and thus confess 

 that they are vegetable productions. 



The slimy substance of the Amo&ba diffluens (Fig. 

 2, e), that we have stated to be continually changingrits 

 shape, like the outline of a cloud, refuses to alter its 

 colour under such a test ; and, moreover, as it flows 

 or glides from place to place, is seen to devour and 

 to digest the materials with which it is surrounded, 

 thus claiming admission into the animal series, and 

 soon making good that claim by exhibiting attributes 

 and capabilities decidedly of an animal character. 

 The remaining forms (Fig. 2, i, 3, 4, 7, 9, 10, 12, 13, u, and 15), 

 more active and energetic in their movements, and 

 evidently of higher capabilities, are all distinguished 

 by having their bodies either partially or entirely 

 covered with a wondrous machinery of vibrating 

 hair-like appendages, which, from their resemblance 

 to our eye-lashes, have been named cilia.* By the 

 assistance of these admirable organs, the little crea- 

 tures possessing them are rowed rapidly about from 

 place to place, or causing whirlpools in the surround- 

 ing water, drag towards their mouths the tiny victims 

 upon which they feed. The vegetable forms above 

 mentioned are known to botanists under the names 

 of Diatoms,^ Desmidice,\ Confervte, &c. The slime- 

 like animals are called by zoologists Rhizopods, while 

 the ciliated forms are distinguished by the appella- 

 tion of Infusoria, 



These, then, are the usual occupants of a drop of 

 water, the contemplation of which cannot but excite 

 the curiosity of the spectator, and call forth his 

 warmest admiration. Curiosity will, however, per- 



* Cilium, an eye-lash. t S/aro/uoy, diatomos, divided. 



% 8eo>ibs, desmos, a band. 



