JAPANESE ASTEEOIDEA. 207 



Paxillœ. — In the largest specimen the paxillae are well spaced, 

 but in the other two specimens, which are smaller, they are 

 rather closely set. In all cases, however, there is a circular central 

 area in the disk, where the paxillae are very dense and just a 

 trifle smaller than those of the immsdiately surrounding parts 

 (PL I, fig. 9, 12). The paxillae also gradually decrease in size 

 towards the tip of the arms. The tabulum is rather long and 

 cylindrical and is provided with an expanded base inbedded in the 

 skin. The coronal spinelets are rather long, slender and pointed, 

 the longest ones being slightly longer than the tabulum ; their 

 number varies according to the size of the paxillae. In one of the 

 largest I have counted as many as fifteen, but in a smaller one 

 near the tip of the arms there are only some ten or less. There 

 is no distinct difierence in shape between the peripheral and 

 central spinelets, but a few around the centre are usually larger 

 than the others. Moreover, the central part of the summit of the 

 tabulum is more elevated than the peripheral part, so that the 

 coronal spinelets of a paxilla usually assume the form of the 

 painter's brush. In the largest of my specimens a good deal of 

 the naked skin is visible between the paxillœ. None of my 

 speoimans is in a condition to show the papular pores. 



Madreporite. — The madreporite is tolerably large, low, nearly 

 circular, and covered with radiating grooves ; the peripheral part is 

 usually more or less overgrown by the surrounding paxillae, but 

 the midreporite itself is entirely naked ; its inner margin is nearly 

 twice as far removed from the centre of the disk as from the 

 superomarginals (PI. I, fig. 13). 



Terminal plate. — The terminal plate is comparatively large and 

 elliptical, the major axis being at right angles to the length of 



