The wall of the tubotheca of the tuboid graptolite Epigraptus eisenacki Mierzejewski has been studied with TEM. It was found that the tubothecal wall is composed of the cortical tissue which differs only slightly from the same tissue described in Dendroidea and Mastigograptus sp. In addition a giant tubotheca in Discograptus schmidti Wiman has been examined with SEM. The tubothecae studied seem to confirm a non-graptolite nature of the organism living in them, while providing evidence that the tubotheca wall was a genuine graptolite structure overgrowing these organisms.
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Tubotheca of Epigraptus eisenacki Mierzejewski: Transverse section of the wall; p - pseudofusellar intercalations. |
