OF WESTEEN SIND. 357 



IV. BemarJcs on the Species. 



Besides the remarks made hitherto we make the following observations. 



The predominant forms of regular Echini in the Gaj series belong to the genera 

 Cidaris, Coelopleurus, and Hipponoe. The species of the last-named genus attain truly 

 gigantic proportions ; and from the fact that they have not been found in older strata, 

 as well as from their not infrequent occurrence in the Gaj series, constitute a characteristic 

 feature in the horizon under notice, and help to emphasize its modern facies. Both the 

 Sindian forms of Hipponoe we consider to be specifically distinct from the H. Sclineideri 

 described by Bohm from the Tertiary beds of Madura*. 



Echinus subcrenatus, unfortunately only represented as yet in the Gaj collection by 

 fragmentary specimens, is in like manner the first appearance in the Sind Tertiaries of 

 that cosmopolitan modern genus, and bears evidence to the approach of the present 

 fauna. 



Of Cidaris we have been enabled to describe two distinct species ; but the presence 

 of other members of the family is proved by the very numerous series of spines obtained 

 by the Survey. Cidaris opipara presents alliances to the two Cidarids described from 

 Kattywar and has a distinctly Tertiary facies. C. excelsa foreshadows in several 

 respects the characters of the recent Goniocidaris. A large number of the isolated 

 spines have a striking Phyllacanthid facies. 



The two species of Ccelopleurus are very common in the Gaj deposits, and the 

 condition of preservation of many specimens is unusually perfect. There has therefore 

 been no difficulty in comparing these forms with the modern Ccelopleurus Maillardi of 

 the Indian seas. The principal distinction between the Miocene and the Eecent species 

 consists in the greater height and want of obliquity of the interambulacral plates of the 

 modern type. We have shown in a communication to the Linnean Society f , that the 

 remarkable arrangement of the ambulacral plates noticed in the fossil forms is well 

 seen in the recent, and we have indicated that this arrangement, more or less modified, 

 is a character of the Arbaciadse. 



The alliance of the modern and the fossil species is very close, and doubtless, did 

 the nature of the fossilization permit, the remarkable dowelling and other structures of 

 the sutures of the plates of the modern form would be found in the ancient. 



The new species Ccelopleurus Sindensis has a granular and hardly tubercular 

 condition of the ambulacra above the ambitus. In all of these Ccelopleuri the optic 

 pore is double and opens on the adoral edge of the radial plate, a process separating 

 the pores. 



It is perfectly evident that d'Archiac and Haime were mistaken regarding the 

 Nummulitic derivation of Ccelopleurus Forhesi. 



Finally it may be said that these Miocene species are about as closely allied to the 

 Oligocene form as they are to the recent. 



The Temnopleuridse are well represented in the Miocene of Sind, and they clearly 



* Denksohr. K. Akad. Wissenseh. Wien, Bd. 45 (1882), p. 362. 

 t Journ. Linn. Soc, Zool. vol. xix, pp. 25-57, 



3c 



