74 THE VOYAGE OF H.M.S. CHALLENGER. 



ANTIPATHARIA, Milne-Edwards. 



Antipathaeea, Dana. 

 Ceratophyta (pars), Gray. 



Colonial Zoantharia, possessing a continuous horny sclerobasic axis, which consists of 

 thin concentric lamella? usually enclosing a central canal. The horny axis is usually 

 more or less branched, and is spinose in all known genera excepting Savaglia. The 

 ccenenchyma consists of the fused bases of the zooids ; it is always thin, and never con- 

 tains any spicules proper to it. The sclerobasis may be independent or parasitic ; in the 

 latter case the sclerenchyma forms a sheath around some foreign body. The colony is 

 generally fixed by a basal dilation of the sclerenchyma, but in some cases this is replaced 

 by an elongate flattened hook-like base ending in a point. The sclerench)'ma is 

 probably a secretion of the ectoderm. 



Family I. Savagliidj, n. n. 



Gerardidx, Verrill. 

 Antipathes (pars), Auctt. 



Antipatharia the zooids of which possess 24 simple tentacles and 24 mesenteries, and are 

 connected together by a ccenenchyma possessing a series of interzooidal canals opening 

 into the base of each antimere. Sclerenchyma parasitic, not spinose. The tentacles may 

 be completely covered in contraction by the anterior portion of the body- wall. The zooids 

 have the typical Actinian structure. 



Savaglia, Nardo, 1843. (= Gerardia, Lacaze Duthiers, 1864.) 



Family II. AntipathidyE, Verrill (emend.). 



Antipatharia in which typically the individual zooids have six simple tentacles, but 

 in dimorphic genera three individuals, each possessing only two tentacles, are morpho- 

 logically equivalent to one zooid of the ordinary type. The tentacles are contractile, but 

 apparently never "retractile." Sclerenchyma rarely parasitic, always spinose, and 

 usually possessing a central canal. The ccenenchyma is not generally traversed by a number 

 of interzooidal canals, but the individual zooids are brought into communication by 

 a stolon-like lateral outgrowth of their ccelentera. Six primary mesenteries are always 

 present, two of which occupy the transverse axis and bear the reproductive organs. 

 There may be six or four secondary mesenteries which are always short, or these may be 

 absent altogether. This family corresponds to the genus Antipathes as instituted by 

 Pallas. 



