of the Anthozoa Tabulata. 13 



of a HalysiteSy the great accordance in their intimate structure 

 is very striking. In both there are the large-sized corallites, 

 and between these a more or less dense coenenchyraa of narrow 

 tabulate tubes. This structure (the " Zwischenwande " of 

 Fischer-Benzon, in his paper " Ueber Holy sites ^'' p. 12) is of 

 a very variable nature both in Holy sites and in the Heliolitidse. 

 Longitudinal sections of Plasmoiwra {Propora) tubulata and 

 Holy sites catenularius resemble each other most; but there 

 is also a great similarity in the initial stages of growth in both 

 genera. In all the Heliolitidie, as well as in Favosites^ Syrin- 

 gopora^ &c., the earliest stage of growth is that of a small, 

 narrow, conical polypary affixed to some other fossil along its 

 whole length. In Favosites and several other corals, new 

 corallites bud out immediately from the inferior lip of the first 

 corallite. In Heliolites and Holy sites ^ again, there is first 

 formed the coenenchyma, as an excrescence of the calicular 

 rim, all around it ; and out of this coenenchyma the new coral- 

 lites are .developed. The difference between the further growth 

 in these last-mentioned genera is only that in Heliolites the 

 new corallites group themselves around their parent ; whilst in 

 Holy sites they range themselves in a line, each new one at the 

 side of its predecessor. Both genera agree also in having, as 

 a rule, twelve septa, which are subject to great variations in 

 size in different corallites, being always of the same size in 

 the same corallite. In some species the septa meet centrally 

 and form a kind of columella, which is elevated and styliform 

 in Heliolites — but in other forms is alone present, the septa 

 having almost disappeared. Where the corallites are large 

 the septa are generally small or quite deficient, as in Heliolites 

 megastonia and Halysites catenularius. In those species, again, 

 which have small corallites, as Halysites escharoides and 

 Heliolites inordinatuSj the septa are proportionally more 

 developed. I, then, consider Halysites to be a member of the 

 Heliolitidae ; and it is not improbable that Thecia^ with its 

 twelve septa and dense tubular coenenchyma, also belongs to 

 the same family. Amongst recent corals Pocillopora most 

 closely resembles the Heliolitidse. 



The genus Battersbyia I have not seen ; but it has been 

 shown by Duncan (Trans. Roy. Soc. 1867, p. 648) to be one 

 of the Astraeidaj. 



Columnaria (or Favistella, which has. the priority) is one 

 of the Cyathophyllidse, as may be seen by its gemmation. 



Fletcheria, represented only by F. tuhifera^ E. & H., seems 

 to be a Cystiphylloid of very variable characters. In the 

 smaller varieties the vesicular endotheca has been converted 

 into tabulae, and the septa have almost disappeared. 



