OF WESTERN SIND. 45 



closely with the generic formula of JEcMnodiadema ; it differs greatly both in the form 

 of the test and in the character of the tuberculation, and differs altogether in the 

 presence of the Salmacis-^^kB slits or grooves in the sutures of the interradial plates. 

 This assemblage of characters readily distinguishes our form, and at the same time 

 debars its admission to any known genus. It is to be hoped that further material will 

 be forthcoming to enable a more complete diagnosis to be drawn up. 



Sulfamily EOHINIB^. 

 Section POLTPOEI. 



A fragment of a large regular Echinid of the Polypore type, with a stout test, has 

 nine interradial plates from the apex downwards preserved ; a corresponding space of 

 an ambulacrum exists, as well as part of another interradium. 



Genus EURYPNEUSTES, gen. nov. 



Test of large size, probably subconoid or subdepressed, not tumid. 



Ambulacral areas very broad, rather narrower than the interambulacral opposite 

 the tenth plate. Poriferous zones very wide, about one fifth of the breadth of the 

 interambulacral area. Pores arranged in three vertical series ; five or six poriferous 

 plates comprised in each whole compound ambulacral plate ; the pairs of pores borne 

 on each are disposed in the zone according to the following order: two or three 

 consecutive pairs of pores form a slightly oblique arc at the outer margin of the zone ; 

 the pair borne on the next more aboral poriferous plate stands in the middle of the 

 zone ; and the pairs borne on the succeeding two plates are placed in slightly oblique 

 sequence on the inner margin of the zone. The outer vertical series thus consists of 

 slightly oblique arcs of two or of three pairs ; the median series, which is somewhat 

 irregular, of single pairs, widely spaced in vertical sequence ; and the inner vertical 

 series of two pairs of pores, which stand to one another in oblique succession. A 

 straight and regular, vertical line of primary tubercles stands at the extreme margin of 

 the interporiferous area on either side ; one primaiy is on each plate, the intermediate 

 space being occupied by a number of very small widely spaced secondary tubercles 

 and miliary granules. 



Interambulacral areas with two continuous vertical series of primary tubercles 

 similar to, and only slightly larger than, the ambulacral tubercles, placed nearer to the 

 poriferous zone than the middle of the plate ; near the ambitus a second and more 

 outward tubercle is present. The inner portion of the plate is occupied by very small 

 secondaries and miliaries. 



In consequence of the wide and trilinearly arranged poriferous zones, this genus 

 presents a closer superficial resemblance to Hippono'e, Gray (Tri^pneusfes, Agassiz), than 

 to any other of the Polypori. In structural detail, however, it is widely separate, and 

 is readily distinguished from any of the known forms by the crenulate tubercles, the 

 number and arrangement of the pores and poriferous plates, and the character of the 

 ornamentation. 



H 



