| The developmental mode of polychaetes is characterized by the production at hatching of an initially unsegmented trochophore larva. |
| To gain a more accurate understanding of the segmented or unsegmented nature of these four taxa, two types of data must be gathered. |
| Slugs and snails have a soft, unsegmented body measuring 2 to 4 cm in length. |
| Moreover, this rod was unsegmented, for the notochord is devoid of segmentation. |
| In lancelets, the trunk somites extend and fuse ventrally to give the unsegmented periviscelar coelom. |
| The fin rays sprouting from the ends are also unique in having a long, stiff unsegmented basal area. |
