Geological Society of London, 133 



absent, and the lumen of the tube is distinguisbable by the ready 

 passage of transmitted light. Other tubes run parallel to the wall, 

 and enter by openings not larger than their common calibre. But 

 there are others which have a larger diameter, and in which the 

 cytioplasm appears to have collected in masses resembling conidia ; 

 and where fossilization has destroyed much of the continuity of a 

 tube, a series of dark and more or less spherical bodies may be seen. 

 In some places, especially in the spaces between the minute curved 

 dissepiments and tabulae, hosts of globular spores, with or without 

 tubes emanating from them, maj^ be seen. In Calceola sandalina 

 corresponding structures exist sometimes, and the method of entry 

 of the parasite can be examined. The author gave two instances, 

 one of which was seen in section. A decided flask-shaped cavity 

 existed in the wall of the shell, opening outwards and rounded and 

 closed inwards. It was crowded with globular spores (oospores), 

 and these, where near the sides, had penetrated the hard shell, and 

 thus gave a rugged and hairy appearance to the outline of the 

 flask-shaped cavity. After noticing minute structures in a Bra- 

 chiopod included in a Silurian Coral, and in a Lower Silurian Fora- 

 minifer, the author asserted, from the results of his late researches 

 upon the algas parasitic in Corals out of his own aquarium, that 

 the fossil and recent forms are analogous in shape, size, and distri- 

 bution. He considers that the old parasite resembles Saprolegnia 

 ferox in its habit; and as he considers that Empusina, Sapro- 

 iegnia, and Achlya — members of the Protista — are the same 

 organisms, living under different physical conditions, he names the 

 old form FalceacJilya penetrans ; and he believes that it entered the 

 wall by the spores fixing on to the organic matter, and growing by 

 its assimilation, and that carbonic anhydride was evolved. He con- 

 siders that this acid, assisted by the force of growth and the move- 

 ment of the cytioplasm, are sufficient to account for the presence of 

 the tubes. Finally, the author draws attention to the probable 

 similarity of external conditions in the Silurian and present times, 

 and to the wonderful persistence of form of this low member of the 

 Protista. 



2. " How Anglesey became an Island." By Prof. A. C. Eamsay, 

 LL.D., F.E.S., V.P.G.S. 



The author described and illustrated by sections drawn to scale 

 the contours of the island of Anglesey and the adjacent parts of 

 Carnarvonshire, and noticed that the whole island may be regarded 

 as a gritty undulating plain, the higher parts of which attain an 

 average elevation of from 200 to 300 feet above the sea-level. 

 Similar conditions are presented by the country for some miles on 

 the other side of the straits, and in both the general trend of the 

 valleys is north-east and south-west. The rock surfaces, when bare, 

 show glacial stride running generally in a direction 30° to 40° west 

 of south. 



The author indicated that the great upheavals of the crust of the 

 earth forming mountains took place long before the commencement 

 of the Glacial epoch, and that ordinary agents of denudation had 



