160 UPPER, OR FLINTY CHALK. 



lamellge ; the latter are perpendicular, alternately reaching to the centre 

 of the axis, where they unite at about 0-2 inch below the margin. The 

 intermediate lamellae are distinct, and do not extend more than half-way 

 towards the axis. The smaller number of the lamellae, and the union of 

 the larger ones, separate this species from Madrepora cyathus of EUis *, to 

 which it is nearly allied. 



The cyathiform variety is represented, Tab, xvi. fig. 2. 



The inversely conical, or turbinated, by Tab. iv. fig. 16. vol. 3. 

 Organic Kemains. 



In some specimens of the elongated or cylindrical variety, a mode of 

 o-rowth is observable, which if not the effect of accident, might constitute 

 a specific, or perhaps a generic character. An example of this kind is 

 delineated in tab. xvi. fig. 4. The coral is attached by its pedicle to 

 a fragment of chalk, and is of a regular cyathiform figure, to the ex- 

 tent of about an inch. From the disk of this joint, it is produced 

 into an elongated cyhndrical body, which is bent nearly at right angles 

 with the base ; a pecuharity of shape that must have resulted either 

 from the original conformation of the animal, or from its having been dis- 

 placed, and subsequently extended in a perpendicular direction. 



The constituent matter of the specimens is crystallized carbonate of 

 Hme, which in some examples is translucent, and exhibits the lamellated 

 structure of the original, in a very distinct and beautiful manner. 



Localities. Brighton, and Lewes chalk-pits. 



6. An unknown species of compound Madreporite.^ 



Of the compound INIadreporites, or those which consist of an aggre- 

 gation of stars, a species has been discovered, that difiers from any 

 previously noticed by authors ; but the specimens in my possession, are 

 not sufficiently entire to point out the form of the original. It belongs 

 to those corals which Mr. Parkinson has designated by the term "por- 

 pital," and occurs in fragments from one to two inches thick. It is 

 composed of fine perpendicular lamellae, united by very numerous hori>- 



* Ellis' ZoopJiytes, tab. xxviii. fig. 7. 



