JR. F. Tomes — Inferior Oolite Madreporaria. 451 



septa, of which twelve are of equal length and form the fossula. 

 The rows of calices are connected by septal costaa, which are nearly 

 parallel, and run towards the outer margin of the lobe. Very few 

 anastomoze, but all, as well as the septa, are regularly papillated. 

 In the fossula is a well-defined columella consisting of about 

 twelve regular styliform papillae. 



Height of the corallum, about 1| inch, and its greatest diameter 

 about 3| inches. The calices are distant from each other about one 

 line. 



I have met with a few specimens in the Oolite Marl at Leck- 

 hampton Hill, but not at any other place. 



DlMORPHAR^IA EXPANSA, Sp. nOV. 



I possess four specimens of DimorpJiarcea, from the Inferior Oolite 

 of East Coker, they are very distinct from Dimorpharcea Oolitica? 

 which I describe as follows : — 



The corallum is very broad and thin, and the upper and under 

 surface have about the same degree of convexity. The largest 

 specimen has a diameter of four inches, while in thickness it does 

 not exceed half an inch. The outer margin of all the specimens is 

 quite thin. In all of them the mural costee are visible on the under 

 surface, only a very small quantity of epitheca being present. This 

 is distributed in patches. These costas are straight, uniform in size, 

 and they radiate from a centre. 



The middle or parent calice has very little prominence, and is only 

 a little larger than the surrounding ones, which are ranged around 

 it in circles, so irregularly that they look almost scattered. 

 There are, however, three circles of secondary calices, and outside 

 the external one the septal costaa are prolonged to a length exceed- 

 ing the distance between the circles. From this it might seem that 

 three is the full complement of circles, unless the distance between 

 the circles increases rapidly as the corallum enlarges. 



From twelve to sixteen septa enter into and form the calices. 

 In the most regularly formed there are twelve, of nearly equal 

 length and thickness, extending to the fossula, but they do not enter 

 into it. They have perforations, which are not numerous, but are 

 large and distinct. The septal costae are of equal thickness with the 

 septa, as well as equally thick throughout; they are straight or 

 wavy, rarely curved, and have a radiate arrangement. The breadth 

 of the intervals between them rather exceeds their own thickness. 



At present I have been unable to examine specimens having the 

 septal edge complete. 



COMOSERIS VERMICULARIS. 



A specimen of Comoseris which I took from the friable Pisolite at 

 Crickley Hill is obviously specifically identical with the specimen 

 I have already referred to C. vermicularis obtained from the over- 

 lying Coral-bed at that place. 1 It is a young and worn example, but 

 is very instructive as to the habit of growth of the species. A short 



1 Quart. Joura. Geol. Soc. vol. xxxviii. p. 448. 



