September 5, 1S84. 



SCIENCE. 



209 



fauna may have been contemporary with several 

 successive marine faunae. At present our knowl- 

 edge of the terrestrial faunae of past epochs is so 

 slight that no practical difficulty arises from using, 

 as we do, sea-reckoning for land time. But I think 

 it is highly probable that sooner or later the inhabit- 

 ants of the land will be found to have a history of 

 their own." 



When these words were written, more than twenty- 

 four years ago, scarcely one of the geological details 

 to which Mr. Blanford called attention was known. 

 He need not point out how wonderful a commentary 

 such details have afforded to Professor Huxley's 

 views. But there is, he believed, an additional distinc- 

 tion between land and marine faunas, that requires 

 notice. At the present day the difference between 

 the land-faunas of different parts of the world is so 

 vastly greater than that between the marine faunas, 

 that if both were found fossilized, whilst there would 

 be but little difficulty in recognizing different marine 

 deposits as of like age from their organic remains, 

 terrestrial and fresh-water beds would in all proba- 

 bility be referred to widely differing epochs. 



Our present knowledge of the distribution of ter- 

 restrial and marine faunas and floras can be only 

 briefly treated. Among mammals and reptiles, the 

 marine forms are generally the most widely diffused. 

 Fishes give better illustration: eighty families are 

 typically marine, and twenty-nine are confined to 

 fresh water; of the first, fifty are universally, or 

 almost universally, distributed ; while of the second, 

 only one (Cyprinidae) is found in five of Wallace's 

 regions, and not one is met with in all six. It is 

 impossible to conceive a greater contrast. The dis- 

 tribution of land and sea Mollusca leads to a similar 

 conclusion as to the relatively narrow range of the 

 land forms. Throughout the marine invertebrata, but 

 few generic types are restricted to particular seas : the 

 majority are found in suitable habitats over a large 

 portion of the oceans. Indeed, the marine provinces 

 that have been hitherto distinguished are founded 

 rather on specific than on generic distinctions. 

 Botany offers a still more remarkable example: so 

 uniform is the marine vegetation of the world, that 

 no separate regions can be established in the ocean, 

 while Drude makes fourteen on the land. 



Mr. Blanford alluded to the evidence of the exist- 

 ence of land-regions in past times. Proofs are already 

 accumulated of differences between the fauna of dis- 

 tant countries in tertiary times. The eocene, miocene, 

 and pliocene Vertebrata of North America differ quite 

 as much from those of Europe as do the genera of the 

 present day; and there was as much distinction be- 

 tween the mammalia of the Himalayas and of Greece 

 when the Siwalik and Pikermi faunas were living as 

 there is now. The reptiles of the American Jurassic 

 deposits present wide differences from those of the 

 European beds of that age. But there is no reason 

 for supposing that the limits or relations of the zoo- 

 logical and botanical regions in past times were the 

 same as they now are. It is quite certain, indeed, 

 that the distribution of land-areas has undergone 

 enormous variations, whether the great oceanic tract 



has remained mfchanged in its general outlines or not : 

 and the migration of the terrestrial fauna and flora 

 must have been dependent upon the presence or ab- 

 sence of land communication between different con- 

 tinental tracts : in other words, the terrestrial regions 

 of past epochs, although just as clearly marked as 

 those of the present day, were very differently dis- 

 tributed. 



The idea that marine and terrestrial faunas and 

 floras were similar throughout the world's surface in 

 past times, is so ingrained in paleontological science, 

 that it will require many years yet before the fallacy 

 of the assumption is generally admitted. No circum- 

 stance has contributed more widely to the belief than 

 the supposed universal diffusion of the carboniferous 

 flora. The evidence that the plants which prevailed 

 in the coal-measures of Europe were replaced by to- 

 tally different forms in Australia, despite the closest 

 similarity in the marine inhabitants of the two areas 

 at the period, will probably go far to give the death- 

 blow to an hypothesis that rests upon no solid ground 

 of observation. In a vast number of instances it has 

 been assumed that similarity between fossil terres- 

 trial faunas and floras proves identity of geological 

 age ; and by arguing in a vicious circle, the occurrence 

 of similar types, assumed without sufficient proof to 

 belong to the same geological period, has been alleged 

 as evidence of the existence of similar forms in distant 

 countries at the same time. 



It may perhaps have surprised some, that Mr. Blan- 

 ford scarcely alluded to any American formations, 

 and especially that he had not mentioned so well- 

 known and interesting a case of conflicting paleon- 

 tological evidence as that of the Laramie group. His 

 reason was simply, that there were probably many 

 present who were personally acquainted with the 

 geology of the American cretaceous and tertiary beds, 

 and who were far better able to judge than he of the 

 evidence as a whole. To all who are studying such 

 questions in America, he thought it would be more 

 useful to give the details of similar geological puzzles 

 from the eastern hemisphere, than to attempt an 

 imperfect analysis of difficult problems in the great 

 western continent. 



THE PHYSIOLOGY OF DEEP-SEA LIFE. 1 



The physiology of the deep-sea life has, until lately, 

 received but little attention from professed physiolo- 

 gists. No one has yet set forth the numerous diffi- 

 culties which are encountered, when the attempt is 

 made to comprehend the mode in which the ordinary 

 physiological processes of Vertebrata and other ani- 

 mals are carried on under the peculiar physical con- 

 ditions which exist at great depths. 



A knowledge of the conditions under which gases 

 occur in a state of absorption in the ocean-waters 



1 Abstract of an address to the biological section of the 

 British association at Montreal, Aug. 28, 1884, by H. N. 

 Moselet, Esq., M.A., F.R.S., Linacre professor of hutnau and 

 comparative anatomy in the University of Oxford, president of 

 the section. 



