SOLITARY CORALS. 



215 



Fig. II. Diagram of a section through the corallum of Heterocyatkus ceguicostatus taken a short distance 

 above the Aspidosiphon chamber. The septa and synapticula are black, the stereoplasm is shaded 

 with dots. 1, 2, 3, endosepta of three cycles, ex., exosepta. sir., stereoplasm. syn.\ synapticulum 

 connecting a primary endoseptum with an exoseptum. syn.*; vyn. 3 , synapticula connecting secondary 

 and tertiary endosepta with adjacent exosepta. 



structure resembling auy single synapticulum of Fungia. Their lower ends pass into 

 the secondary calcareous deposit in the neighbourhood of the Aspidosiphon chamber ; 

 their upper extremities end in free margins at heights varying according as they 

 connect a primary, a secondary or a tertiary endoseptum with an adjacent exoseptum. 

 The exosepta, in addition to this synapticular union, converge towards, and their 

 inner ends unite with, the tertiary endosepta. 



