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 ...

MR. BALFOUR has brought out the second volume of his treatise with admirable punctuality, and zoologists will find it no less valuable than the first. Indeed it is in many ways more attractive than ...

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 ...