556 PEOF. E. J. GAllWOOD ON THE LOWEE CAEBONIFEEOUS [DeC. I912, 



of a narrow plate from which radiate fifteen to twenty closely- 

 packed lamellae, usually in contact throughout this area : the 

 majority of these lamellae are directly coutinuous with the at- 

 tenuated ends of the major septa ; occasionally, additional lamellae 

 appear to he inserted, and occupy positions facing the minor septa, 

 but these do not as a rule reach the central plate, and occur as 

 bifurcations towards the outer margin of the columella. 



The central plate appears to be continuous with the counter- 

 septum, and with one of the major septa which bound the fossula. 

 There appears to be a tendency for the lamellae forming this com- 

 pact columella to separate slightly in the neighbourhood of the 

 calyx in the adult form. 



In sections through the calyx there is also occasionally seen a 

 tendency to the formation of a pseudo-wall dividing off an inner 

 nucleus round the central plate (PI. XLYIII, fig. 1 c). 



The medial area is radiated by very strong major septa, which 

 taper rapidly into fine thread-like prolongations continuous with 

 the lamellae of the columella, the bases of the inner ends of these 

 septa being thickened and fused together to form a pseudo-wall. 



The minor septa are practically confined to this thick pseudo-wall : 

 they are visible in thin transparent sections, as short thick spines 

 alternating with the major septa. A small and inconspicuous 

 septal fossula is present, which is marked by the shortened cardinal 

 septum. 



The outer area is formed of a narrow zone, of somewhat coarse 

 dissepiments, and is not radiated by the septa. This outer zone 

 is only developed in the neighbourhood of the calyx in mature 

 specimens. 



Longitudinal section (fig. Id). — The central columella is 

 seen to be composed of thickened and somewhat undulating, closely- 

 packed, vertical lamellae which are irregularly anastomosing ; but 

 the figured section (1 d) is cut too far from the axis to show these 

 clearly. 



The medial area is composed of a broad zone of somewhat loose 

 vesicular tabulae arranged in oblique rows, the convex surfaces 

 pointing upwards and outwards. The outer area is made up of 

 nearly vertical rows of smaller vesicles, the convex walls of which 

 point upwards and inwards. 



All the specimens of this interesting genus so far collected belong 

 to the same sjiecies. 



Horizon and locality. — Summit of the Seminida-gregaria 

 Sub-zone. Meathop Fell, Arnside District. 



Cakcinophyllfm simplex, sp. nov. (PI. XLYIII, figs. 3 a-3 c & 

 4 a-4: h.) 



Corallum simple cornute, tapering rather rapidly. Surface 

 covered by well-marked, coarse, vertical ribbing, and by distinct 

 but irregular gro\vth-constrictions. Specimens occur measuring 

 up to 2'o cm. in length, with a maximum width of 2 cm. 



