MADREPOEAIMATSr FAMILY — THE FUNGID^. 143 



to the elongate central fossula and parallel with some of the 

 large septa, the synapticula of the implicated interseptal loculi 

 ai-e broken across and rendered visible in their whole vertical 

 height. They can be seen in their relation to the large and small 

 septa. On the sides of the large septa they appear as long 

 narrow continuous ridges separated by grooves, and having a 

 slightly curved direction, but being in the main vertical. Start- 

 ing from the flank of a large septum at some distance below 

 its free edge, the synapticula pass downwards to the top of the 

 dense basal wall. They may be nearly straight in vertical direc- 

 tion in some parts ; slightly curved, concavity inwards, and often 

 looking slightly uj)wards or downwards in others. Towards the 

 outer part of the septum, and near the circumference of the coral, 

 the curving of the synapticula, which are shorter there, is more 

 decided than elsewhere, and the concavity is directed upwards 

 and inwards. Near the axial space the synapticula are short in 

 vertical measurement and curved, concavity inwards. 



So that along an interseptal loculus a succession of vertical and 

 curved ridges, one close behind the other, extends from close to 

 the axial space to the circumference. 



The extreme vertical length of the synapticula varies in the 

 genus ; and in the species under consideration it is 11 millim., 

 and the thickness, calculated from the direction of the axis to cir- 

 cumference, is "5 millim. ; and forty is an extreme number of 

 ridges to find in succession. 



In a few places the vertical ridge is discontinuous, and in others 

 the ridges may be wavy in their vertical course. 



The ridges are of course synapticula broken across ; and there 

 is a groove between each successive pair, very equal in height 

 and length from within outwards. So that a series of ridges and 

 furrows covers the septa at a certain distance from their free edge 

 down to the base. 



On approaching the fractured surfaces and those joining the 

 ridges together, it becomes evident that each interseptal or inter- 

 locular space is open above between the upper parts of the septa^ 

 and that below it is subdivided into numerous canal-shaped spaces, 

 each being bounded inwards and outwards by synapticula, and on 

 either side by septa. There is an open space also near the axis, 

 and this is bounded externally by the first synapticulum. 



The synapticula which are attached to the thin and smaller 

 septa arise close to their free upper edge ; and in all other 



11* 



