Fig. 4

Section-based 3D-reconstruction of the lophophoral base of Asajirella gelatinosa. A Anal view of the transverse epistome muscles with schematic outline of the epistome. B Oblique anal view of the epistome shows the epistome coelom ascending from a narrow canal between the gut shanks. C Anal view of the cerebral ganglion with prominent epistomial horns bilaterally ascending into the epistome. Transverse epistome muscles project in between the epistomial horns. D Anal view of the lophophoral base showing the narrow canal of the epistome coelom above the cerebral ganglion. The epistomial horns continue distally as epistomial neurite bundles. E Lateral view of the lophophoral base showing the dome-like appearance of the epistome and the tentacles supplied by the forked canal above the epistome in the lophophoral concavity. Ganglionic horns project anally of the cerebral ganglion, a retractor muscle inserts proximally of the latter. cg cerebral ganglion, con circumoral nerve ring, ec epistome coelom, eh epistomial horns, em epistome musculature, enb epistomial neurite bundles, ep epistome, epc epistome canal, fc forked canal, gl ganglion lumen, gh ganglionic horns, ph pharynx, rm retractor muscle, tc tentacle coelom