46 THE FOSSIL ECHINOIDEA 



1. EuKTPNEUSTES GKANDis, sp. nov. Plate VIII, Figs. 4, 5. 



The ambulacrum is very wide, but near the ambitus it has not quite the breadth 

 of the interradium there. The poriferous zone is very wide, but it does not equal the 

 interporiferous area in breadth at a slight distance from the apex. The poriferous 

 zones are nearly on a level with the rest of the test, being very slightly depressed ; 

 they are narrow towards the apex, but they soon enlarge, and then remain at very 

 much the same breadth. The series of pores are not crowded except near the apex, 

 where there is a simple succession opposite the first interradial plate ; lower down 

 there is crowding, and some pores are out of the straight line. The third interradial 

 plate (and three below it) has in relation to it two distinct series of pores, an outer 

 and inner, and an indefinite middle series. There is thus a vertical series of pairs 

 of pores on either side of the poriferous zone, and a more incomplete one, with 

 intervals here and there, in the middle part of the zone. Eeally, at the ambitus, there 

 are two vertical series of triple pairs, one pair often being in the middle of the zone. 

 Near the ambitus there are usually six poriferous plates to each whole composite 

 ambulacral plate ; but on the upper portion of the area, and also here and there else- 

 where, one of the poriferous plates is wanting,'and the regular sequence of two sets of 

 triple pairs is destroyed. The pores are large and nearly circular in outline, and the 

 three and two pairs are close, in vertical succession ; but there is some space between 

 the series in all directions. 



The ornamentation of the poriferous zone is scanty; there are a few small 

 tubercles, with slightly crenulated processes, and they are placed in twos or threes 

 obliquely between the succession of the central series of pores. Usually the tubercles 

 are of three sizes, the smallest being nearest the inner row of pores. Many sharply 

 pointed miliaries exist on the ridges between the pores, and are oblong or in linear 

 series. 



The miliaries in linear series are very small, and follow the lines of the junction of 

 the poriferous plates. 



The interporiferous zone is narrow towards the apex, and it soon widens, so that 

 at the level of the tenth interradial plate it is nearly twice the width of the poriferous 

 zone. The plates are double the number of those of the interradial area, and each one 

 carries, near the poriferous zone, a primary tubercle, imperforate and crenulated. These 

 tubercles are smaller than the primaries of the interradial area, and increase in size 

 from above downwards. They are in vertical series, and are well apart ; and the surface 

 of the test' between the tubercles is plain. The remainder of the plate has a few very 

 small and faintly crenulated secondary tubercles on it, and a few miliaries. The 

 number of these small tubercles increases towards the ambitus, and seven or eight are 

 noticed on the largest plates. 



The interradial area has the plates slightly convex from side to side, and the 

 sutures very distinctly marked. One vertical row of large crenulated, imperforate 

 tubercles is on the ambulacral side of the plate, and a second and slightly smaller row 

 is commenced at the sixth plate from the apex. The tubercles have broad bosses arising 



