JAPANESE ASTEROIDEA. Ill 



sliglitly towards its extremity, and is indurated with spicnlar spinelets like 

 the rest of the abactinal membrane. 



" The marginal plates form a deep margin and cmwe over roundly in 

 the interbrachial arcs, the inferior as well as the superior series being 

 visible from above. Upon the rays the superior series arch well over and 

 almost meet in the median dorsal line, giving to the ray a more or less 

 subcariuate character. The supero-marginal plates are four in number from 

 the median interradial line to the extremity, exclusive of the large terminal 

 plate, and all are distinctly longer than liigh. The second and third supero- 

 marginal plates from the median inteiTadial line bear short, conical, upright 

 spinelets ; but all the rest are unarmed excepting the terminal x^late, wliich 

 carries tlnree spines — one at the extremity in the median line of the ray, 

 and one on each side at the anterior extremity of the inferior margin of the 

 plate. The terminal plate is swollen and prominently tubercular abactinally, 

 and is excavated on its outer extremity for the passage of the terminal 

 ambiüacral tube. In one ray of the specimen under notice, the penultimate 

 supero-marginal plates are also swollen and ankylosed in such a manner as 

 to resemble the terminal plate, and bear a single spinelet. 



" The infero-marginal plates, which are five in number, are much 

 shallower than the superior series, and also shorter. The two series conse- 

 quently do not correspond, a result probably brought about by the extreme 

 development of the terminal plate, wliich occupies the space of both superior 

 and inferior plate. 



" One cribriform organ is present in each interbracliial arc ; it is rather 

 broad and has a deep depression down the median line. The structm'e is 

 lamelliform. (See PL XXYII.) 



" The ambulacral fm-rows are wide and open, occupying nearly the 

 whole of the actinal sm'face of the ray. The adambulacral plates are small, 

 and form regular triangular prominences, which indent, as it were, the 

 margins of the fm-row. Their armatm-e consists of two short, subconical, 

 sharply-pointed, or thorn-Hke spinelets, placed side by side on the aboral 

 side of the projecting angle ; they are consequently directed aborally and at 

 an angle towards the fmTow, diverging also slightly from one another. 



