Architecture of the paired anterior ambulacra (II and IV).
Shape of the paired ambulacra. Synapomorphy: external rows of the anterior and posterior paired ambulacra (Ib-IIa and IVb-Va) form a continuous, concave or bow-like curve with each other [ILLUSTRATION FOR FIGURES 1-2 OMITTED].
Apart from the body wall with five ambulacra
, only the mesentery is present in the anterior region after evisceration.
Five of these pairs form the ambulacra
, and they alternate with the five remaining pairs, which form the interambulacra.
The lower stiffness of ambulacra
compared to interambulacra of E.
The space between the rings indicated that the growth rates of plates in ambulacra
were faster than in interambulacra.
One podium (external expansion) and its ampulla (internal expansion) protude from the aquiferous canal alternately on each side along the radial ambulacra
[ILLUSTRATION FOR FIGURE 12C AND D OMITTED].
Nine-day-old metamorphosing larvae look like yolky stars and have the first pairs of tube feet present in four ambulacra
[ILLUSTRATION FOR FIGURES 1I, 2I OMITTED].