68 JR. G. Carruthers — A Revision of some Carhoniferoiis Corals. 



elevation may disappear at that point of the calyx, while in many 

 examples of this species it is not present at all. The feature is 

 commonest in the calices of young specimens. 



The (cardinal) fossula, lying on the convex side of the corallum, is 

 very deep and distinct, extending to, or beyond, the centre of the 

 calicinal floor, and with a characteristically smooth, even outline, due 

 to the presence of a distinct and continuous stereoplasmic lining ; as 

 a rule the fossula is long and narrow, with an expansion at the inner 

 end of varying degree (PI. V, Fig. 4«) ; it may, however, be widely 

 expanded internally, especially in young specimens. 



The minor septa are almost always well developed, although at first 

 sight this would not seem to be the case, since they are fused with the 

 major septa for the greater part of their length, and so give rise to 

 a broad and more or less solid rim inside the top of the calyx, beyond 

 which they project but slightly (PI. V, Fig. 4rt). They taper to 

 a thin point in the interseptal chambers. 



Milne-Edwards & Haime and de Koninck both give good figures of 

 the calyx, but the perspective does not express the peculiar bell- 

 shaped cup very well. 



Average dimensions. 



Height of an adult specimen, 2*5 cm. ; diameter of calicinal rim, 

 1*3 cm. ; depth of calyx, "8 cm. 



Internal Chabactees. 



Transverse Sections. — The major septa show similar characters to 

 those seen in the calyx. They are more or less straight, while the 

 thickening at their outer and inner ends is well shown, being 

 generally rather more apparent in the two cardinal quadrants (PI. V, 

 Fig. 3). As a rule those septa at the counter end of the section show 

 less thickening at their inner ends, and often become subparallel, 

 especially in sections across the younger parts of a corallum. 



The (cardinal) fossula shows great variation in shape, but is always 

 veiy prominent. As a rule in the young parts of a corallum it is 

 more expanded than in the mature portions (PI. V, Figs. \a and 

 3a-3c) ; but the open portion may be very small if the stereoplasmic 

 lining is greatly developed (PI. V, Figs. \a and 3c). The fusion of 

 the inner ends of the major septa with this lining is very complete. 



The cardinal septum only extends down the middle of the fossula to 

 the centre of the section in the very young stages of growth. It 

 rapidly shortens higher up the corallum, so that in sections across the 

 more adult portions it is similar in size and shape to the minor septa. 

 These latter are usually well developed,' and being fused with the 

 sides of the major septa to a great extent, give the appearance of 

 a very thick wall to the coral (PL V, Fig. 1, etc.). The thin 

 pointed ends are sometimes joined with a major septum. They 

 appear very early in the life of the coral, and are seen even in the 

 young stages of growth. 



' I would regard the minor septa seen in PL Y, Fig. 1, as having the greatest 

 length attained in Z. konincki, as here defined. 



