BARNACLES. 177 



down by every summer shower, and, by virtue of their tenacity 

 of vitality, ready to start to life wherever they may find the re- 

 quisite conditions for their existence. 



It is almost impossible to conceive of the outburst of fresh life 

 caused by the return of moisture in tropical climates. Immediately 

 prior to the setting in of the annual rains, the swamps, pools, 

 water-courses, and even the majestic rivers themselves, are well 

 near dried up. The surface of the soil is parched into a layer of 

 impalpable dust, and the remnants of all the minute tribes of 

 plants are carried to and fro by the slightest winds, amongst the 

 dusty particles to which they themselves largely contribute. In 

 them vitality is maintained under the minimum of the conditions 

 essential to its continuance, and without the interposition of this 

 phase of their existence these organisms would soon become 

 extinct. For upwards of two months the rains continue to fall 

 incessantly. The whole country is flooded, and the rivers expand 

 to the proportions of inland seas. But no sooner have the rains 

 and inundations subsided than the mud-laden pools clear down, 

 the magic influences of light and heat are permitted to operate, 

 and in an inconceivably brief period the surface, the bottom, and 

 the body of the waters absolutely teem with the crowded masses 

 of animal and of vegetable life, amidst which the wheel-animal- 

 cules revel in all the luxury of abundance. 



CIRRIPEDS. ORDER CIRRIPEDIA.* 



Every visitor to the sea-shore has doubtless observed the rocks 

 and stones, the timbers of the jetties, or any objects that have 

 been long immersed in the sea, thickly encrusted with shells of 

 remarkable construction, usually known by the name of Barnacles 

 or Acorn-Skclls. On placing a stone or shell thus encrusted (taken 

 fresh from the sea, so that the animals may be in full life and 

 vigour) in a glass of clear sea-water, and watching them atten- 

 tively, the acorn-shells upon its surface will be seen to open, and 

 presently a beautiful feather-like apparatus will be protruded, 

 and again withdrawn. After a few seconds this movement will 

 be repeated, and again and again the feathery structures will be 

 put forth and retracted with such grace, regularity, and precision, 

 that they present an appearance exquisitely beautiful. These 

 are the arms or cirri of the contained animal. When fully ex- 



* Cirrus, a lock of hair : pes, afoot. 



12 



