NEOLAMARCKISM 421 
Lang’s treatment, in his 7ert-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 Zeat-book of £ntomology (1898) has attempted 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. Pfeffer+ opposes the efficacy of natural selec- 
tion, as do C. Emery t and O. Hertwig. The essence 
of Hertwig’s The Biological Problem of To-day (1894) 
is that ‘‘in obedience to different external influ- 
* Der Kampf der Theile tm Organismus. Leipzig, 1881. Also 
Gesammelte Abhandlungen tiber Entwickelungsmechantk der Organts- 
men, Leipzig, 1895. _ 
+ Die Unwandlung der Arten ein Vorgang functioneller Selbs- 
gestaltung. Leipzig, 1894. 
t Gedanken sur Descendens- und Vererbungstheorie : Biol. Cen- 
tralblatt, xiii., 1893, 397-420. 
