OF WESTERN SIND. 197 



Close to the apex the petals are narrow, and appear to proceed originally almost at 

 right angles to the longitudinal axis of the test. They speedily take a rapid curve for- 

 ward, and their course is then almost straight towards the margin, the apparent 

 distance at which they terminate therefrom being comparatively small. The angle 

 enclosed by the anterior pair of petals is about 94°. The poriferous zones are very wide 

 in the median part of the petal, but very narrow and small near the apex, where they 

 occupy the vertical half of the groove, and they also diminish in size towards the outer 

 extremity of the zone. The inner pores are oval, and the outer larger and pyriform, 

 the pairs being- united by a broad furrow, and adjacent pairs separated by well-defined 

 and keel-like costse, on which are one or two somewhat irregular series of small 

 granules. The interporiferous area is nearly uniform in breadth, except at the apex, 

 and is narrower than the poriferous zone at its widest part. The ornamentation con- 

 sists of very minute, uniform, and widely-spaced granules. The antero-lateral petals 

 measure 28 millim. from the apical disk to their extremity (without calculating for the 

 curve at the apex), and are 6-5 millim. wide at their broadest part. 



The postero-lateral ambulacra are three fourths of the length of the anterior petals, 

 measuring 21 millim. long and 5*5 millim. broad. They are in deep grooves, similar to 

 those of the anterior petals, and have a very uniformly broad character, the contraction 

 at the apex being comparatively slight and rapid, and the outer extremity being well 

 rounded. Their course from the apex towards the margin is almost straight, and the 

 angle they enclose is about 62°. The keel of the anterior interradia is not remarkably 

 high, but is emphasized by the depth of the grooves of the antero-lateral petal and the 

 anterior odd ambulacrum. These interradia are very thick and tumid at the margin, 

 and individual plates are more or less tumidly protuberant. The lateral interradia are 

 not higher than the anterior interradia, and have the appearance of being less carinate, 

 although there is a rather prominent protuberance a short distance from the apex, where 

 the general surface of the interradium is flattened and slightly concavely depressed. The 

 odd posterior interradium is narrow and prominently carinate locally. It is flattened 

 close to the apex, then occurs the protuberance, and the general area is again flattened 

 as its breadth expands outwards. Behind the protuberance the test slopes downward 

 with a steep incline to the posterior margin. 



The periproct appears to have been situated on the upper part of the rounding of 

 the posterior margin, but only a trace of its existence can be made out, in consequence 

 of damage to the whole of the actinal portion of the test. 



One fasciole only, which is peripetalous and embraces a large portion of the 

 surface. Passing near to the extremity of the antero-lateral petals, it sweeps with 

 a well-rounded curve which runs parallel to the inner margin of the groove, and 

 extends nearly midway between the extremity and the apex before it is curved back- 

 ward, to cross the lateral interradial area. Its course towards the posterior petals is 

 diagonal, and still directed somewhat inward. At a considerable distance from the 

 margin of the groove of the posterior petal it is deflected outward, and commences the 

 well-rounded sweep which passes near to the outer extremity of the posterior petal, and 

 is then directed inward and upward to cross the odd posterior interradium to join with 



2d 



