( 139 ) 



The number of North American migrants is very great and remarkable. The 

 Hi'tcractitis is the form breeding jirobabi}' to the north of Alaska (?), bnt it is 

 certainly misleading to call it a " Pacific " form,* as it merely extends its wanderings 

 over parts of the Pacific Ocean. 



The result is that the whole ornis, as far as it is not indifferent on account of 

 of its being pelagic or cosmopolitan, is American or more or less closely allied to 

 and conseipicntly most likely derived from American forms. 



The " obvious leaning toward certain Hawaiian dicaeidine forms " t, which 

 Ridgway surmises does not exist, and the " possibility of a former land-connection 

 of the Galapagos Islands with the Sandwich Islands, either continuous or by means 

 of intermediate islands as stepping-stones," does therefore most certainly not 

 become a factor in the problem. 



Considering the distance from the American continent, the great number of 

 species peculiar to the Galapagos, although remarkable, cannot be astonishing. | 

 The footnote on p. 235 (in the Edition of 1890) of Darwin's Journal of Researches, 

 based on a manuscript note of Dr. Sclater, is erroneous, for neither Strix puneta- 

 tissima, nor Pyrocephalus namis, Otus galapagoensis and Zenaida galapagoensis 

 inhabit the American continent. On the contrary, progress of research has shown 

 that the number of species and subspecies confined to the islands is far greater than 

 it was believed to be. 



The Lacertilia are of undoubted American origin, although — ^especially the 

 marine Amblyrhynchus cristatus — local and of considerable interest. 



The Giant Land-Tortoises offer the greatest difficulty. Nearly all authorities 

 agree that it is not probable that they have crossed the wide sea between the 

 Galapagos Islands and the American continent, although, while they are helpless 

 and quite unable to swim, they can float on the water. If their ancestors had 

 been " carried out to sea once or twice by a flood and safely drifted as far as 

 the Galapagos Islands, "§ these ancestors must have been numerous on the 

 continent. It is absolutely necessary to have palaeontological evidence, before we 

 can answer the question whether they existed on the Soath American continent 

 or not ; and the examination of fossil or subfossil bones if any were found on the 

 Galapagos Islands would also, perhajis, have most important results. At present 

 we cannot, therefore, fully answer the qnestion of the origin of the Giant Land- 

 Tortoises on the Galapagos Islands. 



The insect-fauna of the Galapagos Islands is naturally very poor, but there is 

 nothing in it to oppose an American origin. 



The number of the land-shells is not very large. There is said to be some 

 slight similarity with Pacific forms (Darwin, ^c-. p. 416), but it is doubtful if 

 further researches will admit this fact as at all important ; and, besides, we 

 firmly believe, that the distribution of small land-shells on islands is not an 

 important factor for zoogeographical problems, the easy transportation with 

 drift-wood, bamboos, or by floating on the water, disqualifying them to a 

 great extent. 



♦ Ridgway in Proe. U. S. Nat. Miis. v. XIX. p. 4G3. 



t Ridgway, t.c. p 467. 



X On the other band, we have instances where enormous di.stances have not caused any such 

 remarlcable differentiations— for example, on the Azores. Here, however, <lifferent winds, currents^ 

 different geological age and other circumstances have produced quite iliffercnt conditions. Cf. Wallace, 

 Inland Life. 



§ Wallarc, Ixland Lifr, p. 279. 



