It is indeed only among the Eudrilidae that the enclosure of the ovaries in septal sacs is at all general.
No separate spermathecae or septal chambers for the development of the ova and sperm.
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.
The septal bars in bulk, bc, coelom.
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.