Smyth — The Oarhoniferous Coast-Section at Malahide. 19 



Michelinia a£f. meqastoma, Phill. 

 M4and top of M5 = Z, - C. 



Description. — Height up to at least 20 mm. Calyces 20 or more, sub- 

 equal, shallow, with septal striae. Average diameter of calyces, 7 or 8 mm. 

 Abundant vesicular tissue extending from base often up to height of 17 mm. 

 Stereoplasm moderate, not obliterating vesicular tissue. Other characters as 

 in M. megastoma. Near the top of M 5 one bed contains, in addition to the 

 larger colonies, young ones in various stages, the smallest found having but 

 four eorallites. 



Comparisons. — It agrees very well with de Koninck's illustration of 

 M. megastoma in his " Recherches sur les Animaux Fossiles du Terr. Garb, 

 de la Belgique," PI. XIII, figs. 3-3&. 



It is evidently the form referred by Yauglian^ to his M. megastoma (Phill.), 

 Mut. Za. I find it to differ, however, from his description as follows : — 

 Number of eorallites greater, calyces shallow, vesicular tissue abundant, and 

 not nearly concealed by stereoplasm. 



From M. megastoma of the Rush Conglomerate (C™) it seems to differ only 

 in dimensions, the average calyx diameter of the Rush form being 10-12 mm. 

 The present form is probably an earlier mutation of that found at Rush, and 

 possibly intermediate between it and Vaughan's Mut. Z^. Or it may be a 

 variety (i.e. contemporary close relative) of Mut. Z^ ; or even a local form of 

 Mut. Zj due to environment. 



Zaphrentis. 



The commonest^ species at Malahide is Z. densa, Carruthers, which is 

 common at many levels throughout the exposure. A few specimens of the 

 typical Z. omaliusi, Ed. & H., were identified. Z. ambigua, Carruthers, was 

 not found. Z. delanouei, Ed. & H., s.s., occurs from M 3 down to M 9, and is 

 common at M 5 and M 11. A section below the calyx of an M 5 specimen 

 has a diameter of 10 mm. Z. paralleta, Carruthers, was noted at M4 (top) 

 and Mil. 



Zaphrentis junetoseptata, sp. nov. (PI. I, figs. 1-4). 

 M 13 = Gi. 



Description.- — Irregularly cornute. Often one or more strong constric- 

 tions. Epitheca finely wrinkled. Well marked, flattened costae. Length 

 up to about 20 mm. Diameter of calyx about 9 mm. Major septa reach the 

 centre, except just below a tabula. Cardinal fossula on convex side, bounded 



• Q. J. G. S., vol. Ixvii, 1911 (" Burrington Paper "), p. 371. 



= Cf. Vaughan, Q. J. G. S., vol. Ixxi, 1915 (" Belgian Paper "}, p. 34. 



