(2) Their remarkable stability. When the living world around was profoundly changing; 

 when diverse groups were coming into being and then disappearing; when the giant dinosaurs 

 vanished from the face of the earth, having once dominated the animal kingdom, the contem- 

 porary coelacanths, by a kind of defiance of evolution, remained the same in all essential charac- 

 ters. Reconstruction by palaeontologists of fossils imprinted in the geological strata from the 

 Old Red Sandstone right to the Cretaceous have shown this. 



(3) The fact of their being the only survivors of the great group of crossopterygians, the 

 key group from which came the whole of the immense line of air-breathing vertebrates up 

 to man. Furthermore, they became stabilised at a level that is particularly instructive for 

 the history of higher animals : at that when fishes acquired lungs and limbs and set out to 

 conquer the continents. 



If there were no questioning that coelacanths are our direct ancestors, as some have a 

 little hastily declared, at all events they are directly related to those ancestors. They are a 

 source of most valuable information enabling us to perceive an essential stage of animal evo- 

 lution from life itself. ■ And they deliver to us intact a kind of primitively organised verte- 

 brate of an interest that cannot be overrated. 



Their habits are still a mystery, as are the causes for their prodigious survival through 

 the ages and their present restriction to the north of the Mozambique Channel. We only know 

 that they are exclusively carnivorous, feeding on other fishes and living in deep waters. They 

 have been caught between depths of 75 and 200 fathoms on rocky grounds at the foot of steep 

 gradients around the Comoro Islands. They undoubtedly live at greater depths, but as they 

 keep close to the bottom amid masses of jagged basaltic rocks, nets cannot be used to catch 

 them. One day their secrets will be revealed to us but only by the bathyscaph. 



J. M. 

 Under the Southern Cross. 



During the long polar night the Southern Cross shines over the ancient continent of Antarc- 

 tica. It gleams on the crests of the great swell that surges eastwards in the Southern Ocean 

 while moving round the earth. In the cold season, that is, during our summer, cold water 

 masses move northwards to freshen the coasts of America, Africa and Australia, bringing 

 whales, seals and penguins in their train. In volume the Falkland Current has an importance 

 similar to that of the Labrador Current in the northern hemisphere. Like this current it is 

 influenced by the force of the earth's rotation and so comes to hug the coasts of Patagonia, 

 Argentina and southern Brazil. It overlies an immense continental shelf as large as the New- 

 foundland Banks, an area still unexploited, for the seas are rough and there are no fishing boats. 



Cod-fishes are not found here, for the gadids, except for some deep-water species, belong 

 to the northern fauna. But an abundance of large fishes could be taken, belonging to the family 

 Batrachidae and the species Porichthys porosissimas, the southern " bacalao ". The heavy 

 body is edged with long fins along the dorsal and ventral surfaces and is perforated by very 

 numerous mucous pores set in several rows, like so many lateral lines. Over the head, these 

 pores form more of a network. The pelvic fins are placed under the throat. These animals, 

 which may reach over a yard in length, are bottom-dwellers, but little is known of their biology. 



The fauna of the Patagonian Shelf is subject to great physical variations. When the shelf 

 is covered by cold waters, the Antarctic type of fish moves northward, but when these waters 

 recede, the encroaching water layers of the southern transgression bring with them a partly 

 tropical fauna. Now the cold-water fishes retreat to the south or move deeper down on the 

 slope. Throughout the year sedentary forms such as the groupers ( Acanlhislius brasiliensis, 

 A. paiagoniciis) and flat-fishes of the genus Paralichihijs can be found. Undoubtedly the shelf 

 fauna is also rich in hake (Merliiccius gayi, M. hiibbsi), seemingly a family that originated in 

 southern seas, where it replaces the cod-like fishes. On the coasts of South America as well as 



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