152 



PROF. P. M. DUNCAN ON THE ECHXNOIDEA OP THE 



ambulacra which, characterizes Cotteau's Echinobrissus Goybeti from 

 the Cenomauian of the Lebanon. 



I do not propose to alter the determinations of any of the other 

 species of Echinoidea and Mollusca. The late Mr. Davidson was 

 good enough to determine the Brachiopod to be Rhynchonella depressa, 

 Sow., and this common "Upper-Greensand species was found accom- 

 panied by a coral, Thamnastrcea decipiens, Mich., from the same 

 horizon. The commonest species in the collection in our Museum 

 is Hemiaster cenornanensis, Cott., and the only apparent distinction 

 between the type from the French Cenomauian and the forms from 

 the Bag beds is that the posterior ambulacra in the specimens from 

 India are not quite so broad as the others. All the specific characters 

 are present. Hemiaster simil is, d' Orb., is not uncommon, and two 

 specimens are in our small collection. The identity of the French 

 and Indian species struck^me very forcibly, and the species is really 

 a very distinguishable one. Hence the former determinations hold 

 good except in one instance, and the necessary alteration strengthens 

 the view of the Upper-Greensand horizon of the beds which yielded 

 the fossils, or rather, as I put it, of the existence at Bag of a horizon 

 from the top of the Gault to the base of the Chalk with flints. 



The collection from the Museum at Calcutta was then investigated. 

 The first fossil examined was an exquisite Salenia, belonging 

 to the group with very narrow ambulacra, and which has the two 

 vertical rows of ambulacral primary tubercles so closely placed 

 that there is no room for more than an occasional granule between 

 them, in fact to the " petalifera " or " scutigera " group. The apical 

 disk of the Indian form is ornamented with ridges and furrows 

 in the usual radiating manner. But the species is not a new one, 

 for it was recognized and described by the industrious and exact 

 M. Cotteau in the collection obtained by Fraas in the Lebanon. 

 Cotteau called it Salenia Fraasi, and it was found, in the first 

 instance, in the Cenomauian deposits of the Lebanon. (' Ech. nouv. 

 ou peu connus,' 2 e ser. fasc. 4, 1885, p. 59, pi. 8. figs. 1-5.) 



There are numerous specimens of a Cyphosoma in the collection, 

 and they are readily to be identified with the well-characterized 

 Cypliosoma cenornanensis, Cotteau, from the French Cenomanian. 

 The other specimens are Hemiaster cenornanensis and similis. 

 Mr. Blanford's collection was from the marl near Dussai, 15 

 miles west of Mandoo, and many specimens came from the Coralline 

 limestone at Chirakhan. 



The specimens which could be named belonged to Hemiaster 

 cenornanensis and H. similis. Hence Mr. Blanford has given us the 

 evidence that there is a community of species between the marl and 

 the overlying and conformable Coralline limestone. 



Mr. Bose's collection from the marl was next examined. The 

 two Hemiasters were found and also the Cyphosoma already men- 

 tioned. The Echinobrissus is named, according to Mr. Bose, on my 

 authority, but I did not see it until a few weeks ago. Mr. Bose, 

 however, gave me the opportunity, when I examined his specimen, 



