558 Scientific Proceedings^ Royal Dublin Society. 



septn. The central area presents a loose, irregular figure, in which one may 

 pick out an unthickened mesial plate, from which radiate a few lamellae. 



An early transverse section is Lif/wsh-otion-Uke. The septa unite in 

 groups, and thus reach tlie central plate. The central plate and all the 

 major septa inside the inner wall are strongly and equally thickened. 



Only a very poor longitudinal section was obtained, but it shows the 

 mesial plate and the doming of the tabulae. 



Konincliophyllum carlyanense, sp. nov. (PI. XXXVII, fig 3.) 

 Carlyan Limestone. 



Transverse section : — External area composed of about four rows of 

 vesicles regularly radiated by both series of septa. Medial area — major 

 septa, thickened at base, tapering to a point, not reaching central area ; 

 minor septa projecting as strong, blunt teetli; tabular intersections rare. 

 Central area composed of two or three tabular intersections surrounding a 

 distinct mesial plate which is continuous with the counter septum. A fossula 

 is easily made out. 



Longitudinal section : — The tabulae are well spaced. They slope very 

 gradually inwards and upwards until very close to the mesial plate, when 

 they are " tented " up sharply. 



KoniiickophyUum, aff. d, Vau. 

 Hoi.MPATRicK Limestone. 



This appears to differ from the type in two respects — 



(1) The continuity of tlie minor septa is sometimes interrupted. 



(2) Crowding of the vesicles at the inner border of the external area is 



only noticeable in places. This agrees well witli the lower horizon 

 of the present form. 



Arachniophy llitm simplex, gen. et sp. nov. (PI. XXXVII, fig. 1.) 

 Caklyan Limestone. 



Rapidly tapering. Diameter of calyx 25 mm. 



Transverse section : — At a diameter of 10 mm. there are no minor septa ; 

 the major septa, thirty-four in number, all reach the centre. There is a 

 distinct columellar plate continuous with the counter septum. A well-marked 

 fossula is present. Four or five tabular intersections can be seen, but there 

 are no vesicles. 



A section at the bottom of the calyx has the following characters : — 

 Diameter 20 mm, An external area of one to two rows of vesicles, radiated 



