KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 32. N:0 I. 85 



resembles that of Pl. Stella, has regular, simple radii and in breadth it equals ^U of 

 the calicular diameter. The compartments widening outwards. Between the aureolas 

 there is a rich coenenchyma of polyedric tubuli of unequal size, enclosing minute, convex 

 lamellaj, which in each tubulus form two rows, the opposite through their oblique posi- 

 tion dovetailing each other (fig. 23) and thns causing the appearance as if there were 

 funnelshaped dissepiments. Besides there are also long zones of the comraon vesicular 

 appearance. 



This species belongs to the same group as Pl. suprema and Pl. rudis in consequence 

 of its peculiar coenenchyraal traverses, but differs from them throngh its well developed 

 septa and the aureola which resembles that of Pl. stella. 



It has been found in the uppermost limestone beds (A) of Linde klint in Gotland. 



Plasmopora suijrema n. 



Pl. VII, figs. 24 — 26. 



Corallum disciforra, calicles small, scarcely one millim. in diameter, theca only a 

 little exsert, the septa are short or rudimentary, as crenulations in the theca and conse- 

 quently in a longitudinal section only observable as a narrow, black band with faintly 

 fringed edges. The tabulae are horizontal and much distan tiated, leaving a space of some- 

 what more than one millimeter between themselves. The aureola is large, but irregular, 

 its width equals the diameter of the calicle. Its radii, all regularly connected with the 

 septa, are unequal in size, bent, with lateral processes, which even cross a compartment 

 and join two radii. The other coenenchyma is abundant, consists of tubuli of different 

 size, polygonal or rounded. They continue downwards, but are interrupted and enclose 

 more convex lamella? than horizontal traverses. There are also free spaces of vesicular 

 structure. 



This beautiful species has been found in the central Gotland hills of Linde and 

 Löjsta in the uppermost limestone. 



Plasmopora rudis n. 



Pl. VII, figs. 27 — 31. 



The corallum has grown in large rounded, irregular masses, showing, as usual 

 with those from the upper limestone strata, few vestiges of an epitheca. As these 

 strata generally give evidence of being shore or shallo^v water formations in which 

 waterworn and rolled fossils have been embedded, it cannot be expected to lind them 

 so complete as those from the shale beds. The calicles are in the typical variety of 

 the largest in this genus, attaining 2 millims. in diameter. Of septa there are only 

 rudiinents as broad rounded lists covered with innumerable minute warty protuberances 



K. Sv. Vet. Akad. Handl. Btind 32. N:o 1. 11 



