Mr. H. J. Carter on the Structure of the Foraminifera. 331 



toides dispansa and Orbitolites Mantelli, and their correspondences 

 respectively with Cycloclypeus and Orbitolites. He will also have 

 seen how, partly following D'Orbigny's description of the latter 

 genus, I fell into the error of changing the name of " Orbitoides 

 Mantelli " into Orbitolites Mantelli, now evidently an ill-chosen 

 one, — although it should not be called " Orbitoides," whose posi- 

 tion I shall more particularly assign presently. 



It is also questioned by MM. d'Archiac and Haiine if this 

 Orbitolites Mantelli be the Orbitoides Mantelli, D'Orb., of the 

 United States (Tab. p. 363). Yes: it corresponds with the 

 figures given by Dr. Carpenter (Quart. Journ. Geol. Soc. /, c.) 

 of this fossil, which are too faithful to be mistaken. 



Conulites, nov. gen. PI. XV. fig. 7, &c. 



This beautiful little discoidal fossil, which appears to me to 

 have hitherto been undescribed, and upon which the genus is 

 therefore founded, was discovered among a number of Nummu- 

 litic fossils from the valley of Kelat, which were sent to me by 

 Dr. Cook, after whom I have named the species, in commemora- 

 tion of his indefatigable and successful exertions on behalf of 

 geology in that locality. It is not, however, confined to the 

 valley of Kelat ; for I had specimens, imbedded with Nummulites, 

 by me from Scinde, one of which, being a vertical section in a 

 polished pebble of nummulitic limestone, always puzzled me be- 

 fore I recognized the fossil in its free state, while, being partially 

 infiltrated with yellow oxide of iron, it has since enabled me, 

 more than any others, to describe the internal structure. This, 

 together with the external form of the fossil, will be found fully 

 detailed further on, under its proper head, and therefore all we 

 need here is a short generic summary of its description, which 

 is as follows : — 



Gen. char. — Conical, compressed, discoidal ; consisting exter- 

 nally of a spiral layer of rhomboidal chambers extending from the 

 apex to the circumference ; tilled up internally with convex layers 

 of compressed columnar chambers interspersed with white 

 columns of condensed shell-substance; white columns opake, 

 conical, their sharp ends resting on the inner aspect of the spiral 

 layer, and their large ones terminating at the base of the cone, 

 which presents a slightly convex granular surface. 



It will thus be seen that while Conulites, in its conical form, 

 external layer of chambers; and internal columnar chamber- 

 structure is analogous to Orbitolina generally, but more espe- 

 cially to the solid conical forms, it, in possessing the white columns 

 of condensed shell-substance, is also allied to Orbitoides, while 

 it differs from the latter and agrees with Nummulites in the 

 spiral arrangement of the layer of chambers externally. Hence 



