SCHMIDT: ANIMAL GEOGRAPHY 781 



by Gilniore in 1043. This points again to the fact that the imperfections of the 

 paleontological record must be borne in mind, and that closing its gaps must 

 depend upon chance preservations as well as on chance discoveries. 



A body of evidence bearing on the question of direct connection of Africa 

 and South America, with much speculation derived from it, is supplied by the 

 Permian reptiles of the order Mesosauria, and by certain members of the Triassic 

 Rhynchocephalia, which are found in both continents. (See especially Edwin H. 

 Colbert, 1952.) This finds support from the freshwater bivalves of the family 

 Mutelidae, of which no fossils have been found in the northern hemisphere. Even 

 in this case, the imperfections of the paleontological record and the possibility of 

 convergence must be considered, for Myceiopoda dilucuU, described in 1921 by 

 Pilsbry, from the Triassic of Pennsylvania, may belong to this family. 



The leadership among the group of Matthewsians has now somewhat naturally 

 fallen to George Gaylord Simpson, who succeeded Matthew in the position of 

 Curator in charge of Vertebrate Paleontology at the American Museum in 1944. 

 Simpson had occasion to acquire the same kind of broad command of whole suc- 

 cessions of extinct faunas. In a series of essays (1940-1952) he has dealt effec- 

 tively with the difficulties of what appear as exceptional elements in these faunas 

 — like the sudden appearance of the octodont rodents in South America, and the 

 problems presented by the animal life of the West Indies and Madagascar. In 

 1945 he reviewed the whole classification of the mammals, living and extinct. 



Later Land-Bridge Speculations 



Matthew's reputation was so great among his close associates that it is dis- 

 turbing to us to find him little recognized, or to find him even unknown in wide 

 circles of geologists and geographers dealing with the problems of continental 

 connections. Thus, in the face of isostasy, Charles Schuchert (1932) maintains 

 connections from Madagascar to India, from Brazil to West Africa, and from 

 Europe to Greenland. In an essay in the same year, with the title "Isthmian 

 Links," Bailey Willis reduces the connections regarded as probable by Schuchert 

 to narrow and sometimes tortuously crooked isthmuses, following the course of 

 submarine ridges. Schuchert and Willis, on the geological side, thus stand solidly 

 against the ideas of continental drift. Among botanists, one may cite W. H. Camp 

 for his 1947 paper "Distribution Patterns in Modern Plants and the Problems 

 of Ancient Dispersals." He thinks specifically in terms of Mesozoic east-west 

 continent in the southern hemisphere, and more particularly of the origin of 

 whole groups of flowering plants in the southern hemisphere. A European writer, 

 Otto Wittmann, reviewing the problem in Zoogeographica, comes out flatly for 

 a drifting back and forth of the continents (1934-1935). 



The case of the Hipparion bridge, a hypothetical Miocene land connection 

 from Florida to Spain, including the Antilles and North Africa, is an especially 

 flagrant example of post-Matthewsian irresponsibility, for it not only fails to 

 consider the contradicting evidence, but is itself based on conflicting and 

 erroneous interpretations of the fossils involved. Proposed in 1919 by L. Joleaud 

 as a solution of the existence of the horse-like Hipparion in Florida and Spain 

 in Miocene times, it presently was cited to explain all kinds of mammalian faunal 

 relations between the Old AVorld and the New. By 1924 Joleaud had accepted 



