19 



small space as compared with that of Etliinophyllutn and Coscino- 

 pora, and in fact is not continuous longitudinally throughout the 

 corallum. The figui'es represented in PL II., figs. 5 and 7, are 

 taken from the same specimen, the latter with the centre filled 

 by tissue from near the base of the corallum, and the former taken 

 at a point much higher up, at points which in UtJunophyllum 

 would be occupied by the inner and outer perforated laminae, at 

 the periphery and around the central cavity. The intermedial 

 tissue consists of thickened irregular walls of granular calcite, 

 enclosing oval or oblong spaces, or without regular form. In 

 these walls a dense dark, and at times broken, line is visible (PL 

 II., fig. 6), apparently of the nature of a primordial wall; the inter- 

 spaces are all filled with clear calcite. A radial arrangement of the 

 tissue is here and there visible, assuming a septa-like appearance 

 as in F. radiata, Bornemann."^ Towards the base of the cylinder 

 the tubular cavity becomes filled with tissue, and that round the 

 periphery enormously thickened (PL II., fig. 7). Tabulae have 

 not presented themselves to view. The fibrous structure of the 

 w^alls is visible in PL II., fig. 6, and there are many other peculiar 

 features which I am not at present prepared to explain. For in- 

 stance, the so-called proper wall is broken through by pore-like 

 channels of communication, without a corresponding piercing of 

 the secondary fibrous thickening. In other places are a few pores 

 or vertical canals cut across and filled with clear calcite. 



The material before me is not sufiicient in quantity for the 

 projDer elucidation of this form, but I propose to provisionally 

 name it Protopharetra (?) Scoulari, in memory of one of the in- 

 vestigators of South Australian geology, hoping to return to a 

 more detailed study of it at some future time. 



Genus Girvanella. 



In 1878 Dr. H. A. Nicholson and the writer established! the 

 genus Girvanella for flexuous or contorted microscopic tubuli, cir- 

 cular in section, and forming loosely compacted masses. 



The tubes are apparently simple cylinders, without perforations 

 and destitute of partitions. The tubes of the type species 

 G. problematica are from l-600th to l-700th of an inch in diameter, 

 twisted together in loosely reticulate or vermiculate aggregations 

 of a rounded or irregular shape. G. j^roblematica is characteristic 

 of a Lower Silurian horizon in the South-East of Scotland, 

 known as the Craighead Limestone. Dr. J. G. Hinde has 

 shown, J however, that Dr. Bornemann has redescribed similar 



*Loc. cit., t. 7, f. 1 and 2. 



tMon. Silurian Foss., Girvan in Ayrshire, 1878, fascie 1, p. 23. 



JGeoL Mag., 1887, IV., p. 227. 



