1894- NOTES AND COMMENTS. 243 



of the whales, of the land; even the pelagic animals of higher grade 

 have come back again to the surface from ancestral homes elsewhere. 



There was, however, a time when the bottom and shores of the 

 ocean were untenanted ; when, perhaps, physical conditions made 

 their population impossible. Life at that time occurred only in 

 simple forms and near the surface of the central sea. At last the 

 bottom was discovered and colonised. The earliest settlements were 

 not in shallow water, where food supply was scanty and mixed with 

 sediment, nor in the great depths as yet unfavourable to life ; but it 

 is inherently probable, as well as confirmed by palaeontological evi- 

 dence, that the bottom life first found a footing in the deep water 

 around elevated areas. Colony after colony may, it is true, have 

 been " swept away by geological change like a cloud before the 

 wind " ; but when once the outlines of our modern continents were 

 blocked in, then "the first fauna which became established in the deep 

 zone around " them " may have persisted and given rise to the 

 modern animals." 



The sudden and enormous change of conditions accompanying 

 this change of residence soon made itself felt on the creatures of the 

 deep. The results were increase of asexual multiplication and the 

 establishment of colonies, crowding followed by competition and 

 more exacting selection, the acquisition of hard parts, and increase 

 of size. Progressive evolution along these lines would have required 

 no lengthy period to develop, out of those pelagic and soft-bodied 

 ancestors that geologists will never discover, a fauna in all respects 

 similar to that which geologists have already discovered in the Lower 

 Cambrian rocks. 



Thus those aeons which the geologist has loved to imagine as 

 his own, which the evolutionist has demanded, but which Lord 

 Kelvin has denied and Lord Salisbury ridiculed, — they for Professor 

 Brooks are but the baseless fabric of a dream, unproved, unreal, and 

 unneeded. 



The Primeval Lampreys Again. 



Even of the earliest animals which possessed well-developed hard 

 parts, we still know very little ; and it is strange how peculiarly acci- 

 dental are the few important discoveries that have been made. The 

 little Devonian lamprey Pala;ospondylus, for instance, is known to us 

 merely through the circumstance that the Caithness quarrymen 

 happened to alight upon a little patch of good flagstone at a remote 

 spot named Achanarras. It has been found hitherto only in that one 

 quarry and is restricted to one narrow layer of rock. Palceospondylns, 

 however, revolutionises our old ideas of the Class Marsipobranchii, 

 and we have already published communications in Natural Science 

 pointing out its significance. Quite lately still more information has 

 been obtained on the subject, and Dr. Traquair's latest restoration of 



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