Two pairs of setiform, distally curved, barbed adoral
9 (7-38) Adoral
ciliature 360-384 400[degrees] Van As and Characters Basson (1992) (2) Body (D) 82.
We suggest naming the POVL that we describe herein as the adoral
lobe (ADL) to (i) reflect its growth toward the mouth, (ii) distinguish it from adjacent vibratile lobes (present on some larvae), and (iii) recognize a specialized function.
In the oral region, two clusters of cells corresponded to the adoral
CB nerve and ganglion (Fig.
Three days after insemination, both types of larvae had adoral
ciliary bands in which cilia swept toward the mouth.
The presence of serotonergic adoral
ganglia along the posterior rim of the mouth of asteroid, ophiuroid, and echinoid larvae is likely to be a convergent feature, given our current understanding of echinoderm class interrelationships (3).
The jaws of both males and females, present at each interradius, consist of one tooth, one oral shield, two adoral
shields, two oral plates with infradental papillae, and two buccal scales.
The presence of a nervous system in echinoid larvae was first suggested by observations of a putative thickening in the apical area (MacBride, 1914) and the presence of neuron-like cells in the adoral
ciliary band (Mortensen, 1921).
On the ventral surface, the cells around the stomodaeum, about 10 in number, were monopolar and marked the position at which the adoral
ciliated band will form [ILLUSTRATION FOR FIGURE 2A OMITTED].
These are the apical cilia (AC), inner preoral cilia (IPC), outer preoral cilia (OPC), and adoral
region was defined as starting two plates below the lowest ambital plate.
When stimulated by the manipulator arm of a submersible or by very bright lights, this same species, Endoxocrinus parrae, rapidly flexes some or all of its arms in an adoral
direction (Messing et al.