of the Anthozoa Tahuldta. 3 



\\w. j)l;ic(.'ot' the (lissopiiiuMit.s (a.'<, for oxainj)lo, in some Ptycho- 

 plujlla) ^ \waX in the sanu' way as the ilisse]jinients may occupy 

 the phice of the talmhe. This identity of the tabulae and 

 (lisse[)imcnts is perhajjs in no forms so evident as in the Cyn- 

 thophylla^ in which there are frequent passaffes between ])oth 

 these sclerenehymatous secretions, whereby it is demonstrable 

 that they are immediate continuations or transformations of 

 one another. On the other hand, there are llelioliti(hi^ in 

 wliieli a h>nu-itudinal section sliows dissepiniental tissue of <juite 

 a Cystipiiyllidean tyj)e ])artially sui)erseding tlie usual regular 

 tabulae. A compound (h/sfin/ii/l/inn (such as C, cyUndn'cnm, 

 Lonsd.), where the indivitlual corallites are often very narrow, 

 and are each traversed by crowded and regular horizontal dis- 

 sepiments, quite resembles a " tabulate " coral in its longitu- 

 dinal section, aiul cannot be distinguished from one so far as this 

 particular point is concerned. The fact seems to be that some 

 corals which, like Syringopora and Columnaria, have been 

 placed amongst the Tabulata on account of their " floors," are 

 rather to be regarded as llugose corals. It is also very diffi- 

 cult in longitudinal sections to see any great difference between 

 a Michclinfd ov Emmonsin and a (Ujstiphyllum^ all alike having 

 the visceral chamber tilled up with abundant vesicular dissepi- 

 ments. Besides, there are several recent corals of quite remote 

 zoological affinities, such as TuMpora, which are provided with 

 tabulie, thus resembling SyriyigophyUum and Syringopora. 

 Duncan has also sliown how LnpholicUa is provided with tabulaj 

 (Madrepor. of the ' Porcupine' Exp. p. 323). Amongst Meso- 

 zoic genera, Chnisastra'a and Cyathophora, according to De 

 Froraentel (Intr. Pol. Foss. pp. 278, 280), have tabuhi3 so 

 strongly developed as to lead him to place them in the 

 Tabulata. I am of opinion, therefore, that there is no difference 

 of kind between dissejiimental tissue and tabulaj, both belong- 

 ing to the same sort of endotheca. The Rugose corals there- 

 fore, and some other forms, are just as much tabulated as the 

 Tabulata, and the latter are just as much dissepiniental as the 

 former, there being in this respect a complete agreement be- 

 tween the two groups. 



There are, moreover, other animals which in their hardened 

 tissues possess tabula?, or have the cavity formerly occupied 

 by their body divided into compartments by transverse floors 

 placed at tolerably regular intervals ; and these liave therefore 

 been regarded as Tabulate corals, though I think there is no 

 longer any reason for retaining them auu)ngst the Antiiozoa. 

 This is the case with MtUepora, and probably also with Axo- 

 pora. In a former paper ("Anthozoa Perforata of Gotland," 

 p. 3) I endeavoured to show that the polypary of MiUepora 



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