Biological aspects of theoretical shell morphology

Among the available methods in theoretical shell morphology. moving‐frame method, produce the broadest range of shell shapes and appear to emulate most closely the biological processes involved in shell morphogenesis and growth. In addition, moving‐frame methods can easily be enhnneed in both respects by adding operations that are similar in nature to the original procedures. Improvements beyond this point. however. require a qualitative change in approach. The focus of attention must he transferred from the shell lo the soft parts involved in shell construction. This may be done by (1) regarding the soft parts a5 pneus. and (2) controlling their shape and metabolism through morphogenetic programme based on biochemical reactions.