In addition to the musculature of the proboscis and proboscidian sheath, longitudinal muscular fibres are found in the walls of the oesophagus, whilst transverse ones are numerous and united into vertical dissepiments between the successive intestinal caeca, thus bringing about a very regular internal metamerization.
The genital products develop in intermediate spaces similarly limited by these dissepiments and alternating with the digestive caeca.
The inner surface of the intestinal caeca is ciliated, the caeca themselves are some times - especially in the UT hindermost portion of the body - of a considerably smaller lumen than the intermediate genital spaces; sometimes, however, the reverse is the case, and in both cases it is the smaller lumen that appears enclosed between and suspended by the transverse fibres constituting the muscular dissepiments above mentioned.
The main musculature can be seen through the thin skin to be divided into about sixty pairs of muscle-segments (myotomes) by means of comma-shaped dissepiments, the myocommas, which stretch between the skin and the central skeletal axis of the body.
In addition to these parts the following structures may exist in corals:- Dissepiments are oblique calcareous partitions, stretching from septum to septum, and closing the interseptal chambers below.