G40 s. GOTO : 



the skeleton becomes very hard in alcohol and the body is 

 tolerably stiff. In the 5 -rayed specimens the sides are lightly 

 arcuate, but in specimens with supernumerary rays the interradial 

 indentations are deeper and more angular. 



Adamhulacral plates. — The adambulacral armature consists of 

 two series of spines. The inner spines are borne well down in 

 the ambulacral furrow and are three or four in number for each 

 plate, except on the ürst adambulacral plate, which may bear 

 only two. When there are three spines the one at the adcentral 

 end of the plate is smaller than the others, which are subequal 

 in size. The outer spines are borne on the actinal surface of the 

 adambulacral plates and are also three or four in number for 

 each plate, the one at the adcentral end being usually shorter 

 than the rest. When denuded of the spines the adambulacral 

 plates are seen to present two convexities separated by a groove, 

 one facing the ambulacral furrow and the other facing the actinal 

 side and lying on a level with the ventrolateral plates. The two 

 series of spines are borne on the two convexities. 



Mouth-plates. — The mouth-plates are tolerably large and con- 

 spicuous and bear as a rule each two series of somewhat flatten- 

 ed spines. One of the series is borne on the furrow margin of 

 the plate and consists of five or six spines, of which the one at 

 the mouth end is conspicuously large, being sometimes more than 

 twice as broad as the next one, and with its fellow of the other 

 side, forms the oral spines. One or both of the pair may how- 

 ever be sometimes no larger than the next ones. The other 

 series is borne on the actinal surface of the mouth-plate on its 

 abcentral part, is parallel to the first, and consists of five or six 

 somewhat flattened spines with rounded or truncated ends. 



