228 UTILIZATION OF MINUTE LIFE. 



reous joints united to and alternating with horny 

 ones, which gives to the species in question an 

 aspect similar to that of the plants called Equisetum 

 (horse-tail). Isis hippuris is sought for and prized 

 as a curiosity, though the species is not rare. 



The polypes of the genus Tupipora are ex- 

 tremely remarkable, and much prized as curiosities. 

 Their polypidom is composed of a series of bright 

 red calcareous tubes or prismatic cylinders. They 

 form large round tufts, and often considerable 

 masses in the warmer seas. Peron found that the 

 polypes that inhabit these tubes have green tenta- 

 cles, so that large agglomerations of these species 

 appear like tufts of grass or green fields in the 

 ocean. 



The species Tupipora musica is the most 

 common ; its polypidom is of a fine red colour ; it 

 has been termed T. musica because the cylinders of 

 this polypidom call to mind the tubes of an organ. 

 It is found abundantly in the Indian Ocean and 

 American seas. Formerly it was employed as a 

 medicine, but now is only sold as a cabinet orna- 

 ment or a curiosity. 



It would be interesting to cultivate the latter 

 two, and several other allied species, in a warm 

 salt-water aquarium. Such an aquarium might be 

 easily established in the warm greenhouse of Kew 

 and other botanic gardens^ and it should contain 



