192 s. GOTO : 



and thero is a principal and a secondary crest on each, the latter 

 being nearly half as long as the former (PI. lY, fig. G4). On the 

 principal crest there is an irregular row of 12-15 spines, of which 

 the one at the mouth end is conspicuously larger than the others, 

 and the distal ones are mostly larger than the middle ones. There 

 are moreover some half a dozen spines of moderate size on the 

 adcentral part of each plate between the principal and the second- 

 ary crest, and an irregular row of very small spines on the outer 

 surface of the distal half of the plate. The secondary crest bears 

 some six or seven spines, the most proximal of which is larger 

 than the others and lies close on the outside of the large oral 

 spine of the principal crest (PL IV, fig. 65). 



Ventrolaterals. — The ventrolaterals appear to be constant in 

 number in this species, there being two on either side of the inter- 

 radial line. They are small, and bear each some ten or a dozen 

 spines. When denuded of the spines they usually show a hollow 

 portion at the centre (PI. IV, fig. 64). 



Paxillce. — The paxillae are fine, and there is in the disk a 

 central area of very small and thickly set paxillae, which is very 

 conspicuous in some specimens (PL IV, fig. 62). Of the coronal 

 spinelets the centrals and peripherals are distinct, the former being 

 thicker and shorter than the latter (PL IV, fig. 68). In one of 

 the largest paxillse, which are found about the middle of the base 

 of the arms, there may be some 15 or 16 peripherals and some 

 8-10 centrals. The paxillar area at the middle of the arm is 

 nearly two and a half times as broad as the superomarginals of 

 one side. 



Madreporite. — The madreporite is very small and is almost 

 entirely hidden by the crowns of the surrounding paxillae. It lies 



