OF WESTERN SIND. 25 



III. Description of the Fossil Echinoideafrom the Ranikot Series of Nummiditic 



Strata in Western Sind. 



Order ECHINOIDEA ENDOCYCLICA. 



Family CIDABIJDjE. 

 Genus CIDARIS, Klein, 1734. 



The diagnosis of this genus need not be repeated in this work ; but it is necessary 

 to remark that the tubercles are usually perforate, but that they may or may not be 

 crenulated. The pores are non-conjugate. 



There are small portions of a Cidaris in the Eanikot group of strata, but they are 

 not in a good state of preservation. On endeavouring to compare them with the types 

 of the genus which were described and figured by MM. d'Archiac and Jules Haime*, 

 we were surprised to find those carefully delineated fossils absolutely deficient in 

 details of structure by which the species could be identified. The specimen of Cidaris 

 Halaensis, d'Archiac & Haime, can be distinguished generically ; but clearly the pores 

 are non- conjugate, the tubercles are large, and the scrobicules are continuous above 

 and below. No ornamentation or other details exist. Cidaris Verneuili, d'Archiac & 

 Haime, has also a very bad typical specimen. The ambulacra are slightly wavy, the 

 interporiferous zones are broad and have vertical series of broad roof-shaped elevations, 

 two in each zone, and the pores are non-conjugate. In the interradia the scrobicules 

 occupy the lower part of their plates, the median area is large, and the ornamentation 

 is much obscured by the effects of sand-scrubbing. There are, however, more or less 

 radiating series of separate small miliaries with furrows between them. It is with 

 some hesitation that we place some plates in association with this species. The first 

 specimens to be noticed do not belong to the species. 



1. CiDAEis, sp. Plate V, Figs. 1-3. 



In the indiff'erently preserved specimens the perforation and faint crenulation of 

 the interradial tubercles can be distinguished. The interporiferous zone is moderately 

 wide ; and the roof-shaped plates have, in a well-preserved part of the fossil, two 

 miliaries or very small tubercles on them. The pores are non-conjugate. The badly 

 preserved ornamentation of the plates beyond the scrobicular circle is small and has 

 no tendency to be in ridges or series, or to have furrows or lines in the midst. In some 

 places the minute tubercles are elongate and either irregularly placed or alternate. 



The ornamentation of the circle itself is much worn, and was larger than that 

 beyond, being composed of small rounded tubercles. 



The scrobicules are separate above and below, and a single row of small tubercles 

 is between them and the well-marked suture. The areolae occupy the greater part of the 

 plates ; they are sunken near their periphery, bul the bosses soon project as bold cones, 



* Animaux foss. de I'lnde. 



