444 polyp;. 



Plexaures, 

 Of which the thick bark, with non-salient cells, effervesces but 

 slightly in acids *. 



EUNICEA, 



Where the bark, organized like that of the Plexaures, is furnished 

 with projecting mammillcfi, from which the Polypi protrude f. 



MURICEA, 



Where the moderately thick bark is provided with projecting mam- 

 millae, covered with imbricated and rough scales ;}:. 



Primnoa, 

 Where the elongated mammillse become imbricated by hanging one 

 over the other §. 



In the second tribe, that of the 



LlTHOPHYTA, 



The internal axis is of a strong substance and fixed. In 

 Isis, Lin., 



This axis is ramous, and has no cells or cavities on its surface. The 

 animal bark which envelopes it is mixed with calcareous granules, as 

 in the Gorgoniae. In the 



Corallium, Lam., 



The axis is without articulations, and is merely striated on its surface. 

 It is to this subgenus that belongs the 



Isu nobilis, L, ; Esp., I, VII, or Coral of commerce, so cele- 

 brated for the beautiful red colour of its stony axis, and for the 

 high polish of Avhich it is susceptible. It constitutes the object 

 of a lucrative fishery in several jjarts of the Mediterranean. Its 

 bark is reddish and cretaceous. The Polypi, as in many other 

 genera, have eight denticulated arms. 



MELiTiEA, Lam., 



Where the stony substance of the axis is interrupted by knots filled 

 with a matter resembling cork ||. In 



Isis, Lam., 



Or Isis properly so called, it is interrupted by strangulations, of whicli 



* Gorgonia crassa, Gm., Ac. des Sc, 1700, pi. ii ; — G. suberosa, Ell., Cora]]., 

 XXVI, f. p, q, r i—G./riahilis, Lamour., Sol. and Ell., XVIII, f. 3. 



t Gorgonia auiipathes, Seb.; Ill, civ, 2, cvii, 4; — Eun. Umiformis, I«iraour., Sol. 

 and Ell., XVIII, f. 1; — Eun. clavaria, Id., lb., 2 ; — Eun. mammosa, Lamour., add to 

 Sol. and Ell.,LXX,f. 3. 



X M. spicifera, Lamour., or Gorg. muricata, Gm. ; App, to Sol. and Ell., LXXI, 

 f. 1, 2; — M. elongaia, Lamour., Id. f. 3, 4. 



§ Gorg. reseda, Gm. ; Sol. and Ell., XIII, f. 1, 2. 



II Isis ocracea, Esper., I, iv; — Is. coccinea, Id,, III, A, 5. 



