Some molluscs have a trochophorelarva like polychaetes, a characteristicoften used as evidence for close affinitiesamong molluscs, the segmented worms,and other groups. In gastropods and bi- valves the trochophore usually developsinto a veliger,
a planktonic larva that hasa tiny shell (see Fig. 15.11 a ). In many gastropods, part or all of developmenttakes place within strings or capsules of eggs. Cephalopods lack larvae, and the young develop from large yolk-filledeggs. Female octopuses protect their eggsuntil they hatch. The female usually diesafterward because she eats little or noth-ing while guarding the eggs