| The somites are first formed in the neck, and are added successively behind in the unsegmented posterior region of the embryo. |
| In addition to the thorny proboscis, acanthocephalans are distinguished morphologically as cylindrical and unsegmented worms. |
| Slugs and snails have a soft, unsegmented body measuring 2 to 4 cm in length. |
| To gain a more accurate understanding of the segmented or unsegmented nature of these four taxa, two types of data must be gathered. |
| The fin rays sprouting from the ends are also unique in having a long, stiff unsegmented basal area. |
| Phylum Nemertea contains about 1,150 species of unsegmented worms that possess an eversible proboscis contained in a fluid-filled cavity or rhynchocoel. |
