182 Geological Society. 



racterized by great length ; the anterior articular surface is strongly 

 convex, and the posterior correspondingly hollow. In place of the 

 side chamber characterizing the trunk-vertebral centra, is a long 

 shallow pit. An upper and a lower transverse process are given off 

 from an upper and a lower plate, which project from the side of the 

 centrum above the pit ; and these are connected by a short forked 

 cervical riblet. The neural arch is dwarfed ; and there is no spinous 

 process, and no zygosphenal and zygantral mechanism. The struc- 

 ture of these vertebrae indicates a long, mobile, and light neck. In 

 the trunk the convexity of the anterior articular surface lessens in 

 passing from the neck to the loins, the anterior ball gradually sub- 

 siding till the great articular surface becomes plane, the posterior 

 surface retaining, however, a slight hoUoAvness. The trunk-vertebrae 

 have superadded to the ordinary articular processes a mechanism 

 comparable to zygosphene and zygantrum, which must have given 

 great fixity to this part of the vertebral column, contrasting 

 strongly with the flexibility of the neck. The longitudinal side 

 chambers reach their greatest development in the vertebrae refer- 

 able to the fore part of the trunk ; they lessen toward the loins, and 

 are absent from the neck — which is regarded as conclusive of their 

 pneumaticity, and against their having been occupied by cartila- 

 ginous and fatty tissues, which might have equally occurred through 

 the whole length of the vertebral column, and not been limited to a 

 particular region in close vicinity to the lungs. The whole con- 

 struction affords a notable illustration of immense bulk attained 

 with the use of the smallest quantity of bony tissue, which occurs 

 in the form of very thin sheets or plates. The transverse and 

 spinous processes are strengthened by flying buttresses. The vault 

 of the neural canal is beautifully groined, whence the original name 

 Eucamerotus. The author then pointed out the family resemblances 

 between this Isle-of- Wight "Wealden form and the new Colorado 

 Dinosaurs, which have many points in common, but the latter are 

 both generically and specifically distinct from Omithopsis. 



December 3, 1879.— Henry Clifton Sorby, Esq., F.R.S., 

 President, in the Chair. 



The following communication was read : — 



" On some undescribed Comatulce from the British Secondary 

 Rocks." By P. Herbert Carpenter, M.A., Assistant Master at Eton 

 College. 



This communication contains descriptions of seven new Comatulae 

 from the Cretaceous and Oolitic series of Southern England, together 

 with some new facts respecting the Glenotremites paradoxus of 

 Goldfuss, from the Upper Chalk. This species is remarkable for 

 the presence of certain characters which are very conspicuous in the 

 recent Antedon EschricJitii, and also in a new species dredged by the 

 ' Challenger ' at Heard Island in the South Atlantic— namely, the 

 presence of strong ribs on the inner wall of the centrodorsal, five of 



