46 THE TEETIAEY FOSSIL ECHINOIDEA 



Genus EUSPATANGUS, Agassiz, 1847. 

 Urchins of moderate size, and in general depressed. Ambulacral petals rounded, 

 closed, splayed. Ambulacral areas with large tubercles, crenulated and perforated. 

 Fasciole peripetalous, not sinuous, and circumscribing the large tubercles. Posterior inter- 

 radium without large tubercles. A subanal fasciole present environing the anal plastron. 



1. EusPATANGUS AFFiNis, Duncan & Sladen. Plate XII, Fig. 2. 



There is a much crushed specimen from the Nummulitic series of Kachh, the upper 

 surface of which and part of the actinal area are fairly preserved. It has very much 

 the appearance of a Maretia, and especially of those forms which have a faint fasciole, 

 which is not invariable. The test was certainly not high during life, and is now very 

 flat, not from crushing, but apparently from contraction or falling-in after death. It is 

 notched in front, and a bold furrow is continued to the very excentric in front peristome. 



The antero-lateral ambulacra open at a very wide angle, and the poriferous zones are 

 slightly sunken, the interporiferous the broadest, being slightly raised. The posterior 

 poriferous zone is the longest and is curved, concavity forwards. The anterior is deficient 

 in its development of pores for a short distance from the apex, and the line of rudi- 

 mentary hollows representing the position of pairs is directed inwards and forwards ; 

 the remainder of the zone is curved more decidedly than the posterior zone and in the 

 same direction. The ambulacra are broad towards the apical end and become narrow 

 distally, the pores becoming closer and the interporiferous area diminishing in breadth. 

 The pairs of pores are in deep grooves, separated by broad granular costse ; the inner 

 pore is round, and the outer, much the largest, is comma-shaped. 



The posterior ambulacra, much longer than the others, are separated by a low broad 

 keel, and make an acute angle ; they are very slightly sinuous. Narrow and coming 

 to a point distally, they are rather broader midway, and increase to the first third of 

 their length ; nearer the apical system they become narrower. The poriferous zones 

 longer and broader than the others, are sunken and oblique on the sides of the raised 

 interporiferous area; the anterior is more curved than the posterior; and in both 

 especially in the posterior, the pairs of pores nearest the apical end are ill-developed. 

 The apical system is small, the pores close; and the madreporic body extends far 

 back between the posterior ocular plates. There is an excessively faint groove with 

 a rounded keel on either side of the apical system, in which the very small pores of 

 the anterior odd ambulacrum are placed. 



The interradia diff'er much in size ; there are numerous large, sunken, crenulate 

 and perforate tubercles in the anterior and lateral ; they are in four or five concentric 

 rows, and they decrease in size towards the margin. One exists on either side of the 

 median line in the posterior interradium. 



The whole abactinal surface is minutely and distinctly granular with miliaries, and 

 amongst them are sparsely distributed very small tubercles. 



The peristome is large; its outline is more than semicircular, and, behind,, the lip 

 is stout, straight from side to side, and dependent. 



