REPORT ON THE ANTIPATHARIA. <>!» 



further subdivided by the interposition of another pair of mesenteries, giving six in all. 

 It therefore appears as if, within the family, three pairs represent the more primitive 

 arrangement, and that those genera possessing five pairs, as well as Leiopathes with six, 

 have been elaborated from it. This view appears also to be supported by our knowledge- 

 of the ontogeny of the Hexactinia?. Neither Sagartia dohrnii nor Savaglia lamarcki 

 appear to offer any assistance in a solution of the question. The former has been shown by 

 Andres to be a true Actinian. The fact that Sagartia dohrnii secretes a horny basal 

 membrane, which may become tubular, appears to have no phylogenetic value. Many true 

 Actiniaria have the same power. Savaglia has nothing in common with Antipathidte 

 beyond the possession of a branched lamellate sclerenchyma, which, however, is always 

 primarily parasitic, as in Amphianthidse, but which may extend beyond the limits of the 

 foreign basis. The zooid, so far as its structure is known, belongs to the true Actinian 

 type, and has no similarity whatever to the zooid of Antipathidas. The only essential 

 point on which it differs from colonial Actiniaria appears to consist in the fact that the 

 coenenchyma possesses a series of interzooidal canals, one of which opens into the base 

 of each interseptal chamber. It appears probable that some such communications 

 must also exist between the zooids of certain Zoanthidoe (e.g., Epizoanthus stellaris, 

 R. Hertwig). 



The spinose horny axis, which, excluding Savaglia, is peculiar to the Antipatharia, is 

 related through Dendrobrachia to that of certain Gorgonacea. In certain portions of the 

 axis of Dendrobrachia the sclerenchyma is rugose, with a spinose margin. In Acanthoisis, 

 Wright and Studer, the axis consists of short calcareous nodes and more elongate horny 

 internodes. The internodes are rugose with a dentate margin, giving an appearance very 

 similar to the axis of Dendrobrachia. In Gorgonella, Val., the axis is horny and 

 rugose, but without the dentate margin. Thus whilst the spinose sclerenchyma of 

 Antipathidae appears to be linked to that of Actiniaria through Savaglia, it on the other 

 hand is linked to that of certain Gorgonacea through Dendrobrachia. The sclerenchyma 

 of Leiopathes glaberrima too, the stem and main branches of which are always smooth 

 and glossy, appears intermediate between that of normal Antipathidas on the one 

 hand and Savaglia on the other. On this account it appears probable that a truer 

 knowledge of the systematic position of the AutipathidaB is more likely to be obtained 

 by a study of the zooids than by a study of the sclerenchyma. 



Finally, a few points in which the Antipatharia resemble certain other Zoantharia may 

 be indicated ; some of them have been already mentioned. 



A general resemblance between Savaglia and Zoanthidse is most marked, but it is as 

 yet uncertain whether their mesenteries are arranged on the same plan. The arrange- 

 ment in Zoanthidee is most peculiar, and a renewed study of the arrangement in Savaglia 

 is very desirable. 



The Amphianthidse, as R. Hertwig has already pointed out, bear a general resemblance 



