536 DESCRIPTION OF THE MUSEUM. 



each other and uniting by the end ad infinitum, we 

 shall form an exact idea of a sponge. The holes, 

 which are seen in every direction, let in the 

 water to the animals, which occupy the interior. 



The genera corallium,melitcea, isis,antipathes, 

 and corallina compose, with the gorgojiia, the 

 second section, or the polypi corticati. Of the 

 melitaea we have but four species ; they are very 

 various in their colour and occupy nine frames. 

 Several specimens of the white and of the red 

 corallium are placed in one frame ; some of them 

 have their marine envelope, others are without 

 it, polished, or even carved to shew the different 

 forms that are given to that production. Six 

 frames are filled with seventeen species of the ge- 

 nus corallina, and one contains five species of the 

 genus anthipathes; their appearance is much like 

 that of branches of heath, cypress, etc. The axis 

 of the genus isis, is articulated and composed of 

 horny and calcareous substances. One of the five 

 species in the collection, is is encrinula, from the 

 seas of New Holland, is very rare. 



The lamelliferi are placed in the lower part of 

 the chests with \heforaminosi andjluviatiles. 



In the section of the reticulati, we may re- 

 mark the genera cellepora and discopora, whose 

 fibres are excessively delicate, and the retepora 

 cellulosa, vulgarly known under the name of nep- 



