JAPANESE ASTEROIDEA. 341 



The number of granules of the last mentioned row is very varia- 

 ble, and may bo anywhere between five and ten. In addition to 

 the spines and granules above mentioned there may be one or 

 two others not constant in position. 



Mouth- plates. — The mouth-plates are tolerably large, but not 

 very conspicuous, owing to the similarity of the armature of 

 their actinal surface to that of the adambulacral and the adjacent 

 ventrolateral plates. Each plate has the form of a scalene 

 triangle, the two plates being apposed to each other by the 

 longest side, and the shortest side facing the first adambulacral 

 plate (PL XII, fig. 182). On the farrow margin is a row of stout, 

 tolerably long spines, six or seven in number, forming a series with 

 the furrow spines of the adambulacral plates. The one at the 

 mouth end is thicker and somewhat longer than the others, but as 

 it is inserted on a lower level, it hardly projects on the actinal side 

 more than the others. On the actinal surface of each mouth-plate 

 there is a row of three or four blunt, conical spines parallel to the 

 furrow series, of which the one at the mouth end is conspicuously 

 larger than the others. On the rest of the actinal surface are some ten 

 granules of various size and form, a few of which may be spinous. 



Ventrolaterals. — These are very closely set to one another, 

 and extend into the arms to about the sixth inferomarginals 

 from the tip of the arms. Those lying next the adambulacrals 

 are especially large, but those lying next the inferomarginals are 

 much smaller, while the remaining plates are of intermediate 

 size. Except those next the adambulacral plates, the ventro- 

 laterals do not form any regular rows. Some of them are 

 regularly hexagonal, but the majority are more or less irregularly 

 polygonal. Most of the plates bear each a single pedicellaria. 



