THE OLDEST AIR-BREATHERS 295 



apparently unaware of the observations made in this country 

 by myself and Mr. Lesquereux, have held the Spirorbis to be a 

 pulmonate mollusk allied to Planorbis^ and have supposed that 

 its presence on fossil plants is confirmatory of this view, 

 though the shells are attached by a flattened side to these 

 plants, and are also found attached to shells of bivalves of the 

 genus Naiadites. Mr. R. Etheridge, jun., of the Geological 

 Survey of Great Britain, has summed up the evidence as to the 

 true nature of these probably brackish-water shells, and has 

 revised and added to the species, in a series of articles in the 

 Geological Magazine of London, vol. viii. 



The erect trees of Coal Mine Point are rich in remains of 

 Millipedes. The first of these (Xylobius Sigillaria), which was 

 the first known Palaeozoic Myriapod, was described by me 

 from specimens found in a tree extracted in 1852, and this, 

 with a number of other remains subsequently found, was after- 

 wards placed in the hands of Dr. Scudder, who has recognised 

 in the material submitted to him eight species belonging to 

 three genera (Xylobius^ Archmlus^ and Amynifyspts). These 

 animals in all probability haunted these trees to feed on the 

 decaying wood and other vegetable matter, and were un- 

 doubtedly themselves the prey of the Microsaurians. Though 

 these were the earliest known, their discovery was followed by 

 that of many other species in Europe and America, and some 

 of them as old as the Devonian. 1 



The only other remains of Air-breathers found in the erect 

 trees belong to Scorpions, of which some fragments remain in 

 such a state as to make it probable that they have been 

 partially devoured by the imprisoned reptiles. No remains of 

 any aquatic animals have been found in these trees. The 



1 The two first-named genera from the erect trees, according to Scudder, 

 belong to an extinct family of Millipedes, which he names Archiulidoe, 

 and places with other Carboniferous genera in the order Archipolypodj. 

 The third belongs to family Euphoberidse. Proc. R. S. of London, 1892. 



