THE STRUCTURE AND RELATIONS OF TUBIPORA. 675 



c. Remarks on the Zoological position of 

 Tubipora. 



In De Blainville's ' Manuel d'Actinologie,' 1834, Tubipora 

 is placed in the same family, namely, " les Tubipores," with 

 Cornularia and Clavularia. In modern text-books of zoology 

 there is a tendency to place the genus Tubipora in a separate 

 family, and to classify Cornularia and Clavularia with the 

 Alcyonidse, Von Koch (10 and 10 a), however, agrees with 

 the older view, and he says (10 p. 6): "Von den lebenden 

 Formen stehen ihr wohl die Cornulariden am nachsten, und 

 scheint es, dass diese Familie einen sehr urspriinglichen 

 Zustand der Octokorallen reprasentirt/' I am inclined to 

 agree with von Koch and the older naturalists, and have else- 

 where (8) proposed that Tubipora should be included with 

 Cornularia, Clavularia, Sarcodictyon, and allied forms, in one 

 family, which may be called the Stolonifera. 



In order to arrive at any conclusion as to the grouping of a 

 family of animals it is necessary to take into consideration the 

 lines upon which the phylogeny of that group probably pro- 

 ceeded, and consequently, 1 propose to give certain speculations 

 concerning the phylogeny of Tubipora, to which I have been 

 led in the course of my investigation. 



As I pointed out above, there is every reason to suppose that 

 a long series of intermediate forms between the recent Tubipora 

 and a Cornularia-like ancestor must have become extinct. As 

 long as the walls remained unsupported by skeletal structures 

 as they are in Cornularia, it was a matter of impossibility 

 for the corallites to attain any great length. When, however, 

 owing to the formation of a skeleton the corallites increased 

 in length, communications between the individual corallites 

 would be of immense value to the colony for keeping up a 

 continuous and sufficient circulation. If we suppose that the 

 corallites stood as near to one another on the stolon as the 

 polyps do in the recent Cornularia, fusion of the walls of adja- 

 cent corallites and the formation of pores after the manner of 

 the mural pores of Favosites would be not impossible but even 



