22O 



TABULATE CORALS. 



compact, and the tubes are for the most part not in contact 

 with one another in any part of their extent. In cases, how- 

 ever, where the tubes come into contact to any extent, it may 



Fig. 21. A, Two examples of Cladochonus Michelini, E. and H., from the Lower Carbonif- 

 erous of Dunbar, of the natural size ; B, A small example of the same, enlarged five times ; 

 C, A longitudinal section of the same species, enlarged five times ; D, Portion of a colony 

 of Aulopora, sp., from the Devonian (Hamilton Group) of Ontario, of the natural size ; 

 E, Longitudinal section of part of the same, enlarged five times ; F, Cross-section of a 

 corallite of the same, enlarged five times, showing the tabulse ; G, Portion of a colony of 

 Aulopora repens, E. and H., from the Devonian of the Eifel, of the natural size; H, 

 Longitudinal section of part of the same, enlarged seven times, showing curved tabulse. 



not impossibly be found that " mural pores " exist at the points 

 of union. The septa are always quite rudimentary, in the form 

 of marginal striae or vertical rows of tubercles. Lastly, the 

 continuity of the visceral chamber is interfered with (in certain 

 species at any rate) by complete transverse tabulae (fig. 31, E, F, 

 and H), which are usually more or less curved, or even funnel- 

 shaped, but which do not appear to give rise to anything 

 resembling the axial tube of Syringopora. 



The resemblance between the colonies of Aulopora and the 

 basal portions of a Syringopora, as regards general aspect, has 

 been already pointed out ; but there is, nevertheless, no suffi- 

 cient reason, in my opinion, for uniting the two. The reasons 

 for this belief have been already given, but may be briefly sum- 



