221 
of Edinburgh, Session 1880-81. 
the proper tabulae of Favosites or of Syringopora are to be found 
in a peculiar axial calcareous tube which, may often be found in 
the centre of the visceral chambers of the corallites. When present, 
this tube (fig. 1, c) is never continuously developed throughout the 
entire length of the thecae, but becomes dilated at every node (i.e., 
at the levels corresponding with the external connecting-floors) into 
Fig. 1 . — a, Part of a tube of Tubipora musica, Linn., divided longitudinally, 
showing the openings of the canal-system of the connecting-floors into the 
visceral chamber of the polype, b, Part of a horizontal section taken at 
the level of one of the connecting-floors, showing the canal-system of the 
connecting-floor, c, Part of a cofallite of Tubipora divided longitudin- 
ally, showing the axial tube ; in the lower portion of the figure the axial 
tube is laid open. All the figures are enlarged five times. 
a funnel-shaped expansion, which fuses with the wall of the 
visceral chamber. The axial tube itself, so far as I have seen, is 
always open along its entire length, and is not crossed by any 
internal partitions ; nor have I ever observed it to be in any way 
connected with the inner wall of the visceral chamber, except in 
the manner above indicated at the nodal points of the theca. 
The above-mentioned axial tube seems in some specimens not to 
be developed in any of the corallites ; at other times it is developed 
in many of the corallites of a colony, but not in others. Its exist- 
ence was first pointed out by Mr Charles Stewart, F.L.S., in a paper 
which I unfortunately have not seen, by whom it was compared with 
the infundibuliform tabulae and axial tube of Syringopora , a view 
which has been since adopted by Mr Moseley (“ Voyage of II.M.S. 
Challenger,” vol. ii. p. 125). I shall, however, subsequently give 
