96 ANNALS NEW YORK ACADEMY OF SCIENCES 



vice versa, during any past epoch, Mesosaurus would have had to enter 

 the sea in order to get into hoth Africa and South America. 



On account of the intercalated marine Permian in the region where 

 Mesosaurus is found as well as the underlying limestone containing 

 marine lamellibranchs where Stereostemum is found, I am inclined to 

 believe that Mesosaurus was at least semi-marine, if not entirely marine. 

 Its needle-like teeth strengthen this view, because they are adapted to 

 eating soft animals, which must have been far more abundant on the 

 surface of the sea than in the shallow Permian swamps of Brazil, which 

 became dried up again and again, at which time Mesosaurus would have 

 been pushed down to the coast. There is, then, little or no doubt that 

 Mesosaurus could live both in salt and fresh water just as Manatus, and 

 originally Inia, which are now found in Eio Amazonas. This being the 

 case, it could easily have extended its range across the Atlantic, because 

 it was a good swimmer. It could also have gone by way of the European- 

 American coast or from the nearest Antarctic islands to southern Africa, 

 where the distance would not have been much greater than traversed by 

 the giant tortoises (Testudo) or the semi-marine Iguanidw (Ambly- 

 rhynclius cristatus) of the Galapagos Islands. 42 



The mere fact that only Mesosaurus, the best aquatic form, out of 

 sixty-nine genera of Permian and earty Triassic reptiles recently enumer- 

 ated by Broom for South Africa, has been found in South America, is 

 strong evidence that no connection existed between these continents. 

 The absence of this vast array of land reptiles from the corresponding 

 Permian and Triassic deposits of South America is negative evidence, 

 but it appears to me to outweigh the positive evidence of the marine or 

 semi-marine Mesosaurus. i3 



Scaphonyx fislieri Woodward from the Triassic of Eio Grande do Sul, 

 Brazil, is another form which has been used to support the idea of a 

 connection between South America and Africa. According to von 

 Huene, the known fragmentary data, which have been derived from verte- 

 bras and foot bones, indicate that Scaphonyx is distinct from Erythro- 

 suchus of South Africa. He also thinks that both Scaphonyx and 

 Erythrosuchus are related to several forms found in the Triassic of North 

 America. A form of Erythrosuchus is also known from Europe. Here 

 again the ancestral stock, which was widely distributed and gave rise to 

 these genera, is not known. Hence the fact that Scaphonyx of Brazil 

 has a related genus in Africa is not evidence that these continents were 

 connected, because it also had related forms in Europe. The great ab- 



42 I do not believe that the Galapagos Islands were ever connected with South America. 



43 It is to be noted that the region of the Permian deposits of southern Brazil has been 

 inhabited longer than southern Africa, and it is nearly always the natives and not the 

 few scientific explorers who first find strange animals and fossils. 



