AIR-BREATHERS OF THE COAL PERIOD. 289 



on the land. The plant feeders of the period, on the land at least, 

 are all invertebrates, as snails, millepedes, and perhaps insects. 

 The air-breathing vertebrates are not intended to consume the 

 exuberant vegetable growth, but to check the increase of its ani- 

 mal enemies. Plant life would thus seem to have had in every 

 way the advantage. The millepedes probably fed only on roots 

 and decaying substances — the snails on the more juicy and succu- 

 lent plants growing in the shadow of the woods. While, more- 

 over, the vegetation of the coal swamps was most abundant, it 

 was not, on the whole, of a character to lead us to suppose that it 

 supported many animals. Our knowledge of the flora of the coal 

 swamps is sufficiently complete to exclude from them any abund- 

 ance of the higher phaenogamous plants. We know little, it is 

 true, of the flora of the uplands of the period ; but when we speak 

 of the coal formation land, it is to the flats only that we refer. The 

 foliage of the plants on these flats, with the exception of that of 

 the ferns, was harsh and meagre, and there seem to have been no 

 grasses or other nutritious herbaceous plants. These are wants 

 of themselves likely to exclude many of the higher forms of her- 

 bivorous life. On the other hand there was a profusion of large 

 nut-like seeds, which in a modern forest would probably have 

 afforded subsistence to squirrels and similar animals. The pith 

 and thick soft bark of many of the trees must at certain seasons 

 have contained much nutritive matter, while there was certainly 

 sufficient material for all those insects whose larvae feed on living 

 and dead timber, as well as for the creatures that in turn prey on 

 them. It is remarkable that, perhaps with the exception of a 

 very few European insects, no animals fitted to avail themselves of 

 these vast stores of food have been discovered in the coal. The 

 question : " What may have fed on all this vegetation ?" was never 

 absent from my mind in all my explorations of the Nova Scotia 

 coal sections ; but no trace of any creature other than those already 

 mentioned has ever rewarded my search. In Nova Scotia it would 

 seem that a single snail and a single gally-worm were the sole links 

 of connection between the plant creation and air-breathing verte- 

 brates. Is this due to the paucity of the fauna, or the imperfec- 

 tion of the record ? The fact that a few erect stumps have revealed 

 nearly all the air-breathers yet found, argues strongly for the latter 

 cause; but there are some facts bearing on the other side. 



Our gally-worm, if, like its modern relatives, hiding in crevices 

 of wood in forests, was one of the least likely animals to be found 

 Cur. Nat. 19 Vol. VIII. 



