K. M.Brydone--^Furthe}' Notes on the Trimminyham Chalk. 299 



always present, and is set on the base of the succeeding cell, and so 

 deeply sunk that its rather flattened upper surface is practically 

 flusli with the general surface of the colony. This gives the colony 

 its uniquely compact appearance. Every cell bears one or two 

 avicularia, consisting of long slender tubes lying on the front wall 

 with the wider and open end a short way below the mucro, and 

 tapering away posteriorly and sinking gradually into the front wall. 

 Cells which carry at the foot the ovicell of a preceding cell have 

 two lateral avicularia ; those which do not carry such an ovicell 

 (e.g. the first of an intercalated series) have one median avicularium. 



B. Senonian Species. 

 Semieschara Woodsi, sp. nov. (Fig. 11.) 

 Colony usually adherent, occasionally free and unilamellate. Cells 

 hexagonal and arranged quincunciall3\ Aperture approximately 

 oblong and transverse, the upper lip being sometimes rather shorter 

 than the lower, and sometimes slightly convex. This upper lip 

 slopes sharply inwards, and may therefore be overlooked unless tho 

 light is thrown from the foot of the cell. Ovicell very rare, merely 

 a swelling of the foot of the succeeding cell. Avicularia fairly but 



'wM' . J .. 



'%Jt^'^-'^\ 



Fig. 11. 



variably plentiful. They are separate cells, but not vicarious. 

 They are more or less shuttle - shaped, with a small round 

 aperture in the point of the shuttle. The species appears at least 

 as low as the Marsupite zone, but attains its zenith in the base of 

 the B. mucronata zone. It is probably lineally related to Cellepora 

 Michaudiana, D'O., but easily distinguished by the shape of the 

 apertures both of cell and avicularium. 



Semieschara Pergensi, sp. nov. (Fig. 12.) 



Colony adherent. Cells hexagonal, of varying dimensions, arranged 

 more or less quincuncially with a very broad and ill-defined common 

 wall. Front wall arched from side to side, and also sinking slightly 



Fig. 12. 

 from the foot (where it is almost on a level with the top of the cell- 

 wall) towards the aperture. The aperture is semicircular and large, 



