Through the ever loving Science Book Club I got: Cells, Embryos, and Evolution. Gerhart and Kirchner. Blackwell Science 1997. Paperback. This is not exactly readable, but browsable, and the real low down on morphological evolution. Hox (1) genes and the like. Worth a look. Best wishes, John
1) Homebox ... regulator genes ... affect the timing and magnitude of action by other genes. High degree of commonality exisits in hox genes in similar species (jb note)