THE OPINIONS OF NEO-LAMARCKIANS 521 



tials which distinguish series and groups from each 

 other." 



Packard 1 in discussing the causes of the blindness 

 of cave animals, says: "Such a phrase as < natural 

 selection,' we repeat does not to our mind definitely 

 bring before us the actual working-causes of the evo- 

 lution of these cave organisms, and no one cause can 

 apparently account for the result. The causes are 

 ' change in the environment,' disuse of certain organs ; 

 'adaptation/ ' isolation/ and ' heredity' operating to 

 secure for the future the permanence of the newly orig- 

 inated forms as long as the physical conditions remain 

 the same." 



In 1889, Ryder described the ontogenetic origin of 

 the articulations of the cartilaginous fin-rays of the 

 Salmo fontinalis, and used the facts observed as evi- 

 dence that these articulations are due to the mechan- 

 ical strain experienced by the rays in use as motors of 

 the body of the fish in the water. 2 



Prof. H. F. Osborn in i8go 3 discussed thoroughly 

 the mechanical causes for the displacement of the ele- 

 ments of the feet of the ungulate Mammalia from 

 linear to alternating relations. (See antea, p. 299.) 

 In an article in Nature^ the same distinguished natu- 

 ralist remarks: "The following views are adopted 

 from those held by Cope and others, so far as they con- 

 form to my own observations and apply to the class 

 of variations which come within the range of paleon- 

 tological evidence. In the life of the individual, adap- 



l"On the Cave Fauna of North America," Memoirs of the U. S. National 

 Academy of Sciences, IV, pt., I., p. 137. 



^Proceedings of the American Philosophical Society, 1889, p. 546. 



3 Transactions of 'the American Philosophical Society, XVI., February, 1890, 

 P- 531- 



^January 9, 1890, p. 277. 



