In some species certain of the legs bear on their ventral sides furrows with tumid lips and lined by smooth non-tuberculate epithelium; they are called coxal organs, and it appears that they can be everted.
So high as heaved the tumid hills, so low Down sunk a hollow bottom broad and deep, Capacious bed of waters.
The leaves, which are borne in pairs at the tumid nodes, are oval in form and have a Dicotyledonous type of venation.
The long, slender stems, somewhat tumid at the nodes, were ribbed, the ribs running continuously through the nodes, a fact correlated with the superposition of the whorled leaves, the number of which in each verticil was some multiple of 3, and usually 6.