APPENDIX. 143 
highly organised groups. However, since the hypothesis of the South Pacific land- 
bridge, so far as mammals are concerned, rests largely upon the alleged closeness of 
relationship between Thylacinus and, e. g., Prothylacinus, the question need not be 
further discussed until the debated point is settled, if capable of settlement, by the 
osteological experts concerned. 
The difficulty of the South American Monkeys Mr. Matthew also surmounts by 
appealing to convergent evolution (p. 216). That is to say, the resemblances between 
the Monkeys of the Old and New Worlds have been independently acquired from 
Asiatic and South American Lemurs respectively. | 
This possibility was long ago considered, and rejected, by Mr. Beddard, but was 
adopted by Dr. Scharff. The supposed South American Lemurs—Mr. Matthew admits 
that this group is ‘‘ very doubtfully represented in the early ‘Tertiary formations of the 
Argentine ”—must have passed, he thinks, into South America from North America 
during the Eocene, if I understand him aright. However that may be, I agree with 
Mr. Beddard that it is difficult to believe that the relationship between the Cebide 
and Simiide is no closer than Mr. Matthew suggests. 
In connection with the Hystricomorpha, Mr. Matthew admits that “ we find serious 
difficulties ” (p. 229). After discussing the question, he concludes: “I have been 
unable to frame any hypothesis which will fit all the facts of the distribution of this 
group, except by assuming that the South American Hystricomorpha..... reached 
South America from Africa in the Oligocene by over-sea raft-transportation. ‘This 
involves so long a voyage that I hesitate to accept it as a reasonable probability, even 
though the winds and currents obviously favor transportation in this direction” 
(p. 231). Since this suggestion does not seem to be seriously entertained by its 
propounder, it does not call for further comment. 
The presence of Manatees in the tropical rivers of West Africa and tropical East 
America is explained by the hypothesis of the former existence of the genus up the 
eastern and western shores of the Atlantic into the Arctic Ocean, to a point where his 
map (p.174) shows the extreme north-eastern corner of Greenland may have been 
connected with the north-eastern corner of Europe—that is to say, almost to the pole. 
This theory will certainly account for the facts; but, until the genus Trichechus 
turns up in far northern Tertiary deposits, there is no direct evidence to support it. 
Although Mr. Matthew deals mainly with the Vertebrates, he remarks in connection 
with the supposed transatlantic bridge between Africa and South America: “The 
supposed evidence in its favour from lower vertebrates and invertebrates is due, so far 
as I have been able to examine it, to a lack of appreciation of the principles of 
dispersal of races and of parallelism and of the imperfection of the geological record ” 
(p. 231). Presumably he holds the same opinion regarding the supposed bridge 
between South America and Australia. Nevertheless, I cannot bring myself to believe 
