White J S, Baird I L
Scan Electron Microsc. 1982;3:1301-12.
Comparative fine structural studies of amphibian auditory structures in urodeles have been extended to include examination of the papilliform end-organs (amphibian, neglecta and basilar) that variably occur in species selected from three families of caecilians (Gymnophiona). The species investigated were Ichthyophis kohtaoensis (Ichthyophiidae), Dermophis mexicanus (Caeciliidae) and Typhlonectes natans (Typhlonectidae). Ichthyophis is the only form to display all three papillae; both Dermophis and Typhlonectes lack a basilar papilla but all three species show both neglecta and amphibiorum. In these forms, the amphibian papilla contained the most sensory cells with ciliary bundles organized into two proximal and distal groups polarized toward a mid-line papillar axis. The papilla neglecta contained slightly fewer sensory cells and ciliary bundles oriented predominantly posteriorly. In Ichthyophis, the basilar papilla contained the lowest sensory cell counts of any papilla. Here, basilar sensory cilia were unidirectionally polarized away from the saccule. All papillae were overlain by an essentially similar, extracellular tectorial body. When compared to auditory end-organs in the urodeles and anurans, similar conditions in caecilians are suggestive of a common ancestry for the basilar and amphibian papillae; features of the amphibiorum indicate further that it may represent part of a "displaced" papilla neglecta.
对有尾两栖动物听觉结构的比较精细结构研究已扩展到包括对蚓螈（无足目）三个科中选定物种中不同出现的乳头状终器（两栖乳头、忽略乳头和基底乳头）的检查。所研究的物种有考艾岛盲游蚓（盲游蚓科）、墨西哥盲螈（盲螈科）和纳氏穴居蝾螈（穴居蝾螈科）。盲游蚓是唯一显示出所有三种乳头的形态；盲螈和穴居蝾螈都没有基底乳头，但所有三个物种都有忽略乳头和两栖乳头。在这些形态中，两栖乳头包含最多的感觉细胞，其纤毛束组织成两组，近端和远端组朝向中线乳头轴极化。忽略乳头包含的感觉细胞略少，纤毛束主要向后排列。在盲游蚓中，基底乳头的感觉细胞数量是所有乳头中最少的。在这里，基底感觉纤毛单向极化远离球囊。所有乳头都覆盖着一个基本相似的细胞外盖膜体。与有尾两栖动物和无尾两栖动物的听觉终器相比，蚓螈中的类似情况表明基底乳头和两栖乳头有共同的祖先；两栖乳头的特征进一步表明它可能代表“移位”的忽略乳头的一部分。
