KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 32. N:0 I. 97 



This species comes near to Prop. speciosa but differs in a being entirely without 

 any septal spines in the calicles and in having the vertical element of the coenenchyma 

 more fully developed. 



It has been found near the river Olenek, Sibiria and also on the shores of Petschora 

 in north Russia. 



Propora bacillifera n. 

 Pl. X, figs. 8—21. 



As to the synonymy of this exclusively Lower Silurian species I have no certain 

 data, to which to refer, but it is highly probable that a great number of specimens of it 

 from the Baltic and North Germanic localities have been called Prop. tubulata, by various 

 authors. 



This coral has grown in pyriform, elongated or globular masses, also sometimes 

 disciform. 



The calicles attain in some localities as from Hulterstad in Öland (fig. 12) larger 

 dimensions than is general amongst the Heliolitidaä, viz. 3 mm. in diameter, the other 

 specimens having only 2 or even 1 millim. The calicles are surrounded by a thick theca, 

 having the shape of a twelve-pointed står. The interiör angles of this står make the basis 

 of the septa from which long, pointed, upwards directed spines project, placed remote from 

 each other. The septal lamella proper is reduced to a narrow ridge, scarcely perceptible 

 in a longitudinal section. Owing to the long spines the remote tabulse are not regularly 

 grown, often curved or convex. 



The coenenchyma is a tissue of large bladders, the convex laminse forming it being 

 of the largest kind. It is penetrated by numerous long, slightly curved remote rods or 

 bacilli, having the same colour as the theca and the septa (tigs. 9 and 20) and finish 

 upwards in a fine point. In transverse sections they ressemble small black döts between 

 the calicles (fig. 16). They grow evidently faster than the convex lamellaj and in advance 

 of them as they on the natural surface of the corallum stånd out above these lamellaa. 



There can be observed certain local variations; so for instance, the Öland specimens 

 (fig. 15) have shorter bacilli fixed on the lamella;, as large aculaj. In the specimens from 

 Hohenholm, Dagö, the septal spines do not attain the same length as in the specimens of 

 older geological age. 



It has been found at Treberga in the parish of Hulterstad, Öland, at Osmundsberg 

 and Östbjörka in Dalecarlia, at Hohenholm in Dagö, at Piersal {F^) and Borkholm (i^^) 

 in Estland, very abundant in the last locality, also in Norway at Herö near Porsgrund 

 and is consequently chiefiy a Lower Silurian species. In detached fragments it has been 

 found on the shores of Gotland, near Wisby and at Westergarn. 



