558 PROP. E. J. Gi^RWOOD OX THE LOWER CARBONIFEROTJS [DeC. I912, 



pheral zone of dissepiments. The septa are somewhat flexuous and 

 thick, tapering towards their inner ends, which either reach to the 

 centre, or else coalesce with adjoining septa forming groups of which 

 one septum is continued to the centre. In more mature stages a 

 septal fossula is present and the central plate becomes more 

 irregular, but can be seen to be continuous with the attenuated 

 inner end of the counter-septum (PI. XLYIII, figs. 2 « & 2 d). 



A zone of dissepiments is developed, which becomes wider as the 

 diameter of the calyx increases ; this zone is radiated bj"" fine 

 major and minor septa, the latter being continued into the medial 

 area as short thickened spines ; in a section having a diameter of 

 32 mm. there are fifty stout major septa in the medial area, which 

 become rajjidly attenuated where they enter the central area, and 

 also decrease in thickness in the peripheral zone. 



A longitudinal section shows a vertical undulating median plate. 

 The tabular are rather widely spaced and arch steeply where they 

 intersect the median plate (PI. XLYIII, fig. 2 e). 



The dissepimental zone is finely vesicular and of moderate 

 width, and the vesicles are arranged in vertical rows. 



This form resembles in general characters LojjliopltyVum clierneij- 

 ense Carruthers.^ It differs from that species in having a much 

 more elongated form, in possessing a greater number of septa which 

 are thickened in the medial area, and in having strong minor septa. 



Horizon and localities. — Seminida-yregaria Sub-zone. 

 Meathop-Marsh Quarry, Arnside District ; Marton, Furness 

 District. 



LoPHOPHTLLTJ^r FRAGILE, Sp. UOV. (PI. XLIX, figS. D CI &, D h.) 



Corallum cornute ; epitheca smooth, with occasional growth- 

 constrictions. 



Transverse section. — Septa straight, numerous and delicate, 

 not thickened, not reaching the centre, but continued outwards to 

 thetheca; inner wall inconspicuous. Central area with a short, 

 thin columellar plate, tlie major septa projecting only a short dis- 

 tance into this area. Concentric intersections of the tabulae few 

 in number : appearing as broad bands, on account of the flat and 

 generally horizontal disposition of the tabulae. External area very 

 l)road, radiated by both the major and the minor septa ; dissepi- 

 ments numerous and fine ; cardinal fossula poorly developed, only 

 indicated by the slightly-shortened cardinal septum which stops 

 short of the central area. 



Longitudinal section. — Dissepimental area broad, nearly as 

 wide as the central area; tabulae thin and rather widely spaced, 

 frequently showing a marked tendency to a horizontal arrange- 

 ment, but curving sharply upwards near their intersection by the 

 columellar plate. 



This species is distinguished by its slightly-developed columellar 

 plate, the delicate structure of the septa and dissepiments, the short 



1 Trans. Eoy. Soc. Edin. toI. xlvii (1909) pi. i, figs. 1 & 2. 



