82 



THE ZOOLOGIST. 



each original type is admitted ; in the latter the power of 

 variation is supposed to be very great.* 



Thoughtful and experienced naturalists have long felt some 

 difficulty with the question of the origin of the various species of 

 plants and animals both fossil and recent. Such a question 

 arises, for instance, in reflecting on the close affinity between the 

 skeletons and soft parts of the various vertebrates. Lamarck 

 was the first who hinted that they might all be produced by 

 variation from a few ancestors. He reduced these ancestors, 

 indeed, to two, the vibrio and the monad, and that these sprang 

 from inorganic matter by spontaneous generation. On the one 

 hand the development led through the annelids, cirripeds, and 

 shell -fishes to fishes; and on the other — from the monad — through 

 rotifers, polyps, starfishes, insects, spiders, and crabs. The 

 class of fishes thus derived its several characters from trans- 

 muted squids and crabs. From the fishes the development pro- 

 ceeded through the well-defined vertebrate pattern up to man. 

 Evolution further, according to Lamarck, depended on acquired 

 characters. Buffon had previously advanced the opinion that 

 man was one of the forms originally created, and tbat monkeys 

 and the lower mammals were degenerated human beings. This, 

 perhaps, was a more comfortable doctrine than that of the 

 eccentric Lord Monboddo, who held, even before the time of 

 Lamarck, that men were descended from the monkeys, that the 

 ourang-outangs were members of the human species, and that 

 in Bengal there existed human beings with tails. The list of 

 authors who have enunciated more sober doctrines in relation to 

 the development of existing from pre-existing species includes 

 names very eminent in natural science, as well as the anonymous 

 author [now known to be Dr. Robert Chambers] of the well- 

 known 1 Vestiges of Creation,' a work wherein what is called 

 the progressive development theory is expounded. The author 

 of the ' Vestiges ' believed that all forms sprang from a single 

 cell, and even this cell from inorganic matter, and that the 

 several series of animated beings, from the simplest and oldest 

 up to the highest and most recent, were, under the providence 



* The Darwin-Wallace communication " On the Tendency of Species to 

 form Varieties ; and on the Perpetuation of Varieties and Species by Natural 

 Means of Selection" was made to the Linnean Society on July 1st, 1858. 



