186 NATURALY SCIENCE. Marcu, 
Paleozoic, Mesozoic, and Tertiary ocean in south-western Eurasia, 
but admit also great recent changes in the middle or southern Atlantic. 
Geological evidence, therefore, does not prove, nor even point to, a 
permanence of the great depths, at least in the oceans of the Atlantic 
type. 
Let me remark in a few words that, although I believe in the 
possibility of the formation of large new depressions, I do not hold 
with the old opinion, lately taken up again by M. Faye, that the con- 
tinued sinking of the ocean beds may force chains of mountains to: 
appear all round. This view could only be propounded for the 
Pacific basin; but the Pacific chains are folded in the direction 
towards the ocean, and not from the ocean. They are easily divided 
into arches, each of which presents the convex side to the ocean, so 
that the Pacific everywhere presents the character of a “‘ vorland.” 
Let me, at the end of this long note, allude to a broad biological 
fact. inthe higher beings we see Jungs always preceded by gills; 
so it is even with the humanchild. The adaptation for breathing our 
atmosphere is of a later date; and we conclude that the whole terres- 
trial air-breathing fauna is a derived fauna, derived from amphibious. 
forms quitting shallow water. This fact evidently points toa long 
existence of dry land, long enough to permit this accommodation to 
be effected; the accommodation clearly has been going on since 
Paleozoic times. Still there exists no proof that individual continents. 
always remained the same, and we even know for certain that 
such was not the case with by far the greater part of these 
continents. 
A similar lesson is also taught by the eyes in all the higher 
organised beings of the deep sea. The optical apparatus of abyssal 
species is profoundly modified by the exceptional environment, while: 
the normal types of eyes are met with in the same genera within 
moderate depths. Therefore, we must also regard these deep-sea 
forms as derived forms. The blind and blinded Trilobites of Cambrian 
beds, the blind Trinuclei and the widely-expanded eyes in certain 
species of Aeglina in Lower Silurian strata teach the same lesson. 
At the same time, they show that deep-water must have existed over 
Bohemia, and over a good many other Paleozoic tracts, and that the: 
depths were considerable enough to call forth these same abyssal 
metamorphoses of the eye. 
We might, therefore, rather be induced to infer that in Pre- 
palzozoic times there may have existed a universal hydrosphere or 
panthalassa covering the whole of the planet. Only with the first 
appearance of dry land began the deposition of clastic sediments. 
The higher forms of life may have been developed in waters 
of moderate depth and may successively have spread to the sun-lit 
continents, and to the dark depths, while the slow elaboration of 
the existing inequalities of the terrestrial surface was going on. 
But this elaboration is still in progress. I believe with Reyer, 
