Fig. 24. Planktonic larvae of various invertebrates. 



1. Pilidium larva of nemertine worm. 



2. Actinotrocha larva of Phoroms. 



3. Cyphonautes larva of a sea moss, Memhranipcra. 



4-7. Gasteropoda (univalve molluscs): . , , ,, r 



4. Nassarhis reticulata {a) larva just after hatching; (/>) old larva with sheU forming. 



5. Nassariits iucrafsata, old larva. 



6. Actis minor, old larva with shell forming. 



7. Littorina littorca (periwinkle) {a) young larva; (/)) later larva. 



continued opposite 



