JAPANESE ASTEROTDEA. 369 



varying from five to seven on each plate ; and on the actinal sur- 

 face of the plate there are, in the basal part of the arms, three 

 longitudinal rows of shorter spines, each row consisting of from 

 three to five. The still more external group of shorter spines, 

 referred to by Dödeelein as forming a transition to the granules 

 of the inferomarginals or ventrolaterals where present, belongs 

 undoubtedly to the ventrolateral plates. On the first adambula- 

 cral plate, the ambulacral row of spines is straight ; and in the 

 more distal part of the arms the shorter spines on the actinal 

 surface of the adambulacral plates are frequently more irregular 

 than in the more proximal part, so that they may form more 

 than three rows. 



Mouth-plates. — The mouth-plate is comparatively narrow and 

 elongated, and there are distinctly three sides to it, viz. the 

 longest, almost straight side, by which it is apposed to its fellow, 

 the second side facing the ambulacral furrow, and the third side 

 turned towards the first adambulacral plate, the second and third 

 sides forming a distinct angle between them (PI. YIII, fig. 132). 

 The side facing the first adambulacral plate is longer than the 

 second. The longest side by which the mouth-plates are apposed to 

 each other are frequently united with that of the fellow plate by a 

 few transverse trabeculse. There are about seven rather long spines 

 on the furrow margin of each mouth-plate, the one next the 

 mouth being not longer than the others (PL VIII, fig. 131). On 

 the side facing the first adambulacral plate there are one, two, 

 or sometimes three rather long spines forming the continuation of 

 the last mentioned row, and the triangular area enclosed by the 

 third sides of the two mouth-plates is covered with some twenty- 

 five to thirty short blunt spines, similar to those of the ventre- 



