OF SEA-ANEMONES. (io 



Another point of importance is temperature. It 

 is well known that the extent of the variations of 

 temperatm-e is less in the water than in the atmo- 

 sphere. In the temperate zones (lat. 50° in the part 

 of the Atlantic which is nearest Europe), whilst a 

 thermometer in the latter medium ranges from 66° 

 to 35°, in the former the variation extends only from 

 68° to 41°. Therefore, in imitating this natural 

 law, we must guard our captives from lengthened 

 exposure to the sun in the summer time, and in 

 winter from very hot rooms, and from the extreme 

 cold of the external air. An average temperature 

 of 55° Fahrenheit will agree very well with our 

 friends' constitutions. 



The last caution I need give is with regard to 

 Ught. Water is less transparent than air : it is 

 denser, and transmits light with more difficulty. 

 All the anemones habitually live during a certain 

 portion of the day in a state of comparative twilight 

 But many of them (e. g. the " daisy," the " cave- 

 dweller," the "gem") conceal themselves in nooks 

 and angles of the rock, and beneath huge stones, 

 where little if any light can affect them. We must 

 then endeavour to imitate this condition of their 

 existence by the aid of a north aspect, or of shaded 

 receptacles containing abundance of angular rocks 

 or corals. 



Let me recapitulate the five points of our treaty 

 with the anemones : — 



g3 



