All vertebrate embryos follow a common developmental path due to their common ancestry. All have a set of very similar genes (the homeobox genes) that define their basic body plan. As they grow, the ...

IT is generally acknowledged that land-living plants have sprung from some algal source: that the land was invaded and that the invaders show form and structure adapted to sub-aerial life. If this be ...

IT is scarcely possible to exaggerate the expressions of gratitude which are due from zoologists to Mr. Balfour for the execution of the great task which some three or four years ago he set himself.