NEOLAMARCKISM 



421 



Lang's treatment, in his Text-book of Comparative 

 Anatomy (1888), of the subjects of the musculature 

 of worms and Crustacea, and of the mechanism of 

 the motion of the segmented body in the Arthro- 

 poda, is of much value in relation to the mechanical 

 genesis of the body segments and limbs of the mem- 

 bers of this type. Dr. B. Sharp has also discussed 

 the same subject {American Naturalist, 1893, p. 89), 

 also Graber in his works, while the present writer in 

 his Text-book of Entomology {\%(^'S)\i^.s2X\.e:TCiT^X.&A to 

 treat of the mechanical origin of the segments of 

 insects, and of the limbs and their jointed structure, 

 along the lines laid down by Herbert Spencer, Lang, 

 Sharp, and Graber. 



W. Roux* has inquired how natural selection 

 could have determined the special orientation of the 

 sheets of spongy tissue of bone. He contends that 

 the selection of accidental variation could not origi- 

 nate species, because such variations are isolated, 

 and because, to constitute a real advantage, they 

 should rest on several characters taken together. 

 His example is the transformation of aquatic into 

 terrestrial animals. 



G. Pfefferf opposes the efificacy of natural selec- 

 tion, as do C. Emery:}: and O. Hertwig. The essence 

 of Hertwig's The Biological Problem of To-day (1894) 

 is that " in obedience to different external influ- 



* Der Kamff der Theile itn Organismus. Leipzig, 1881. Also 

 Gesammelie Abhandlungeii uber Entwickelungsmechanik der Organis- 

 men. Leipzig, iSgg. 



t Die Unwandlung der A rten ein Vorgang functiqneller Selbs- 

 gestaltung. Leipzig, 1894. 



\ Gedanken zur Descendenz- -und Vererbungstheorie : Biol. Cen- 

 Irallilall, xiii., 1893, 397-420. 



