92 



This substance is very rarely discovered fossil ; but Scilla 

 states that he found it in the neighbouring hills of Messina, 

 in a mineralized state, reduced to lime, mixed with echini, 

 shells, &c. in a similar state. He found the choral in beau- 

 tiful branches as well as in fragments ; the whole surface 

 deprived of its colour; although, in some of the thicker frag- 

 ments, a purplish hue might still be found in the internal 

 parts*. 



Silicified fragments of this substance are sometimes found 

 among the Blackdown fossils, showing, by their transparency, 

 the beautiful red colour remaining in the internal part. 



Melitcea. — A fixed dendroidal polypifer, composed of 

 an articulated, nodose axis, and of a permanent corticiforra 

 incrustation. 



The central axis is caulescent, ramose, formed of stony 

 substriated portions joined by rather spongy and tumid 

 articulations. 



The cortical crust, in a living state, is fleshy and polypi- 

 ferous ; when dry, it is thin and cellular. 



The Melitaeas differ from the Isides, the following genus, 

 in the character of their articulations, the joints in the 

 former, though stony, being spongy and tumid ; but in the 

 latter, horny and contracted. 



1. Mel. ochracea. . . . Isis ochracea. Lin. Soland. 



2. — retifera. . . . Isis auraulia. Esp. Supp. ii. Tab. ix 



3. — textiformis. . . . South Seas. 



4. — coccinea. . . . Isis coccinea. Sol. and Ellis, Tab. xii. fig. 5. 



This genus has not been described as a fossil ; but the 

 writer is of opinion that a fossil specimen of one of its 

 species is in his possession. 



Isis. — A fixed dendroidal polypifer, composed of a jointed 

 axis and a corticiform crust, not adherent. 



* De Corporibus marinis lapidescentibus, &c. Angustino Scilla, 

 Romse, p. 55. Tab. xx. fig. 1. 



