C 464 ] 
Imperatus feems to have border’d upon this difco- 
very, when he fays, “ that the extremities of the 
“ madrepora are loft, of an obfcure purplifh colour, 
“ containing a membranous fubftance ; from whence 
“ one might lufpedt, that it partakes of a fenlitive 
(t and animal life.” 
Our autnor made the experiment here laid down 
upon every fpecies of madrepora, which he found, du- 
ring the three months he continu’d upon the coafts of 
Barbary. He obferv’d always the fame appearance, 
allowing fome little difference for the colour and 
lize of the animals, the texture of their bodies, and 
that of the bodies themfelves, upon which they were 
produced. 
From what I have here extracted concerning the 
coral and madrepora, an idea may be formed of the 
millepora, lithophyton, corallines, and fponges ; each 
of which is, according to our author, the habitation 
of numerous animals, and form’d by them. He 
has given us from his own obfervations particular 
accounts of each of thefe productions, and divided 
them into genera and fpecies with great accuracy ; 
and though in common they are the habitations of 
animals, each fpecies varying in form and bulk, and 
compofing its cell in various forms and manners, 
and of different confidences, conflitutes their effential 
character. As oyfters, fcallops, mulcles, cockles, 
fnails, &c. have a power given them by the Author 
of nature of forming and enlarging their feparate 
dwellings ; to thefe bodies, the fubjedts of this treatile, 
the fame power is given, but in large families. 
In the madrepora, its animal occupies the extre- 
mity j in the millepora, the fubftance j in corallines 
and 
