The branchial bars which constitute the borders of the clefts are of two kinds: - (i) Septal bars between two contiguous clefts, corresponding to the primary bars in Amphioxus; (2) Tongue bars.
No separate spermathecae or septal chambers for the development of the ova and sperm.
Interradial septal ridges, passing into the taeniolae (f.t) in the stalk.
The septal bars in bulk, bc, coelom.
It is indeed only among the Eudrilidae that the enclosure of the ovaries in septal sacs is at all general.
In forms such as Lucernaria and Charybdaea, in which the umbrella is of deep form and the stomachcavity consequently of great extent in the vertical direction, the concrescence-areas or septal nodes are drawn out into vertical partitions or taeniolae (fig.
The first dorsal spinal nerve coincides in position with the myocomma which separates the first myotome from the second on each side, and thereafter the successive dorsal roots pass through the substance of the myocommata on their way to the skin; they are therefore septal or intersegmental in position.