Geri G A, Kimsey R A, Dvorak C A
J Comp Neurol. 1982 May 1;207(1):99-103. doi: 10.1002/cne.902070110.
It is estimated by means of electron microscopy that the optic nerve of the turtle Pseudemys scripta elegans contains 394,900 fibers of which approximately 80% are myelinated. The total fiber count agrees well with counts obtained from electron microscopic studies on other turtle species. There are, however, differences among these species in the percentage of myelinated fibers in the optic nerve. The axon diameter distribution of the myelinated fibers (excluding myelin) has a mode at 0.87 micrometer while that of the unmyelinated fibers has a mode at 0.42 micrometer. Both distributions are unimodal and are of a similar form in all areas of the nerve sampled. The total fiber count reported here agrees well with previous reports of ganglion cell counts in Pseudemys and the characteristics of the fiber distributions are comparable to those reported for nonreptilian vertebrates.
通过电子显微镜估计，锦龟（Pseudemys scripta elegans）的视神经包含394,900根纤维，其中约80%有髓鞘。纤维总数与对其他龟类物种进行电子显微镜研究得到的计数结果非常吻合。然而，这些物种的视神经中有髓鞘纤维的百分比存在差异。有髓鞘纤维（不包括髓鞘）的轴突直径分布在0.87微米处有一个众数，而无髓鞘纤维的轴突直径分布在0.42微米处有一个众数。两种分布都是单峰的，并且在神经采样的所有区域中形式相似。此处报告的纤维总数与之前关于锦龟神经节细胞计数的报告非常吻合，并且纤维分布的特征与非爬行类脊椎动物的报告结果相当。
