It. F. Tomes — Inferior Oolite Madreporaria. 397 



of the small corallites are not numerous, being about 21 or 24 in 

 number, that is to say, there are three cycles. Of these the septa of 

 numbers one and two pass up to the columella, and those of cycle 

 number three often bend towards and become attached to the earlier 

 ones. In the larger corallites there are a great many more septa, 

 and the cycles cannot be traced owing to their anastomozing so much. 

 In the calicular surface of the peduncle I have mentioned there are 

 at least fifty septa, and the older ones unite with each other, mostly 

 in pairs, quite close to the columella, into which when united they 

 often pass, while the newer ones run into the older ones at points 

 more or less remote from the columella, according to their age. I 

 have not as yet met with a perfect calice, that is to say, one in which 

 the septa have their margins uninjured, and I cannot therefore 

 describe them with any degree of completeness, but so far as I can 

 observe, there is no ornamentation of any kind on their sides. 



The columella is rather large, rugged, and spongy ; its upper 

 surface having about ten or twelve papillse. It is deeply seated in 

 the calice, and has no convexity. 



The height of the corallum has not been ascertained. 



Genus ? 



I have met with some portions of a dendroid Coral at Crickley and 

 at Cooper's Hill, near Cheltenham, which I have failed to place 

 satisfactorily. Its ramifications closely resemble those of Donacosmilia 

 Wrighti, and increase takes place by lateral gemmation near the 

 calice, just as in that genus, and there is usually a constriction at 

 the attachment of the new corallite to the old one. As in Donaco- 

 smilia there is a well- developed epitheca. But it differs essentially 

 from that genus in having numerous and very thin septa which 

 have their sides ornamented by rather numerous and well-defined 

 vertical ridges, ending in prominent points on their upper margins. 

 The earlier formed cycles meet in the centre of the visceral cavity, 

 and there form a rugged columella, which has its upper surface 

 toothed like the margins of the septa. Where the epitheca has been 

 worn off, numerous dissepiments are exposed. 



I am at present unable to refer this species to any known genus, 

 and the specimens are too fragmentary to admit of the formation of 

 a new one. 



EXPLANATION OF PLATE X. 



Fig. 1. Platastrcea endotheeata, sp. nov., the under surface of the corallum of a 



small specimen (natural size). 



„ 2. ,, ,, a portion of a larger specimen (natural size) showing 



the form of the calices and the continuity of the 

 septa. 



„ 3. ,, ,, the upper margin of a septum, magnified four times 



to show the denticulations. 



„ 4. , , , , a portion of the lateral surface of a septum, magnified 



five times to show the regular and arched dissepi- 

 ments. 



,, 5. Placophyllia gracilis, sp. nov., the corallum, natural size. 



,,6. ,, ,, a calice magnified four times. 



