122 ON THE FOSSIL CORALS OF THE 



opposite side. The septa are also sharp-edged for about half the 

 distance from the bottom of the cup to the margin, then become 

 gradually less projecting until at the edge of the cup they are re- 

 duced to mere flat rounded ridges. Length from four to five inches 

 or a little more. "Width of cup from two inches to two inches and a 

 half. Depth of cup about one inch. 



Yery numerous specimens of young individuals of this species, one 

 inch and a-half and upwards in length, and with fifty or more 

 principal radiating septa, occur along with those full grown. These 

 small ones might perhaps be regarded as constituting distinct species, 

 but when good specimens can be observed they all exhibit the 

 characters which are persistent in the large individuals. 



The presence of the columella seems at first sight to be a sufficient 

 ground for placing the individuals in which it occurs in the genus 

 Lopliophyllum (Edwards and Haime). I have, however, examined a, 

 great number of specimens and have found every gradation between 

 the following characteristics. 



1st. Specimens with a perfectly smooth space in the bottom of 

 the cup, no columella. 



2nd. With a columella slightly developed. 



3rd. Columella large and prominent, with a smooth space all 

 round. 



4th. Columella well developed, but with a number of irregular 

 often elongated tubercles in the surrounding smooth space. 



5th. The septa reaching the columella, no smooth space. 



6th. Septa covering the columella. 



7th. Septa reaching the centre, with the columella either promi- 

 nently, slightly, or not at all indicated beneath. 



This last mentioned form must certainly be regarded as a true 

 Zaphreniis, all other characters of the genus being present, and from 

 it there is a regular series of forms leading in the seven directions 

 above indicated or more. It appears to me, therefore, that so far from 

 these specimens being divisible into several genera they only 

 constitute one species. 



The most persistent characters are the rounded edges of the septa 

 near the margin of the cup, and the oval shape of the septal foasette, 

 in the bottom of which where it reaches the side of the cup is a 

 single septum which projects a little and partially divides thefossette. 



This species somewhat resembles Z. cornicula (Lesueur), but 



