124 PEOF. p. M. Duncan's ee vision op the 



separate basals and enter tlie ring. Periproct small ; plates 

 uniform in size except close to tlie anus, where tliey are small, 

 tuberculated. 



Ambulacra straight, broad, with four to six rows of primary 

 tubercles, plain and imperforate, with circles of granules around 

 them, scarcely smaller than those of the interradia, all but the 

 external series disappearing towards the apex ; poriferous zones 

 broad, with small tubercles between the pairs. Pairs of pores in 

 arcs of four pairs or triserial ; the inner row consists of adoral 

 pairs in the adoral primary plates of the compound plates ; 

 tbe outer vertical row consists of series of two pairs closely 

 superimposed, and separated by a tubercle, they are in middle 

 demi-plates ; the middle vertical row has its pairs separated by 

 a tubercle, and they are in tbe aboral demi-plates. 



Interradia with many, from 9-14, vertical rows of primary 

 tubercles, similar in structure to those of the ambulacra, dimi- 

 nishing to two vertical rows abactinally; an irregular median 

 area witbout tubercles ; scrobicular circles large ; miliaries 

 parallel to the horizontal sutures, and vertically between the 

 tubercles ; secondary tubercles scattered irregularly. 



Peristome large, flush, decagonal, witb broad and deep bran- 

 chial incisions. The buccal membrane with ten large plates with 

 spines, pedicellarise, and tentacles, also other spiniferous small 

 plates. Spines short, sharp, finely striated. 



Becent. Sandwich Islands, Philippines, Mauritius; shallow 

 water. 



Grenus Etjetpneustes, Duncan Sf Sladen, 1882, Pal. Ind. ser. xiv., 

 Foss. Ech. W. Sind, pt. ii. p. 45. 



Test large, subcorneal, depressed. 



Ambulacral areas very broad, only rather narrower than the 

 interradia. Poriferous zones broad, and the pairs of pores tri- 

 serial. Plates very low and numerous, composed of five or six 

 component plates, very close vertically, the adoral plate a very 

 low primary, its pair of pores being near the interporiferous 

 area ; the other plates demi-plates, or sometimes the aboral 

 component is a primary ; the successive pairs have a tendency to 

 be close to the one immediately above, and then to be distant, 

 but the inner and outer rows are fairly persistent, and the 

 middle variable in position. Two vertical rows of small crenu- 



