van Veen T
Cell Tissue Res. 1982;222(2):433-44. doi: 10.1007/BF00213223.
The parapineal organ of the glass eel (elver) consists of approximately 400 cells and is situated to the left of the connection of the pineal stalk to their ventricle. A conspicuous nerve tract containing approximately 350 fibers arises from the parapineal organ and runs in spatial relationship to the habenular commissure toward the left habenular nucleus. The dominating cell type of the parapineal organ of the elver is a neuron (sensory neuron) of small diameter provided with atypical cilia (9 x 2 + 0, or rarely 8 x 2 + 0 types). Well-developed photoreceptor outer segments are lacking, and no interstitial cells of ependymal type have been observed with certainty in the parapineal organ. The axonal processes from the nerve cells form the tract leaving the parapineal organ. The pineal organ proper of the elver consists of photoreceptor cells with well-developed outer segments, interstitial cells of ependymal type, and ganglion cells. Axons from the latter form the pineal tract, which leaves the pineal organ and runs in close contact with the subcommissural organ toward the posterior commissure. The proximal part of the pineal stalk contains only a few photoreceptor cells the outer segments of which are less developed than those of the pineal body and the distal part of the pineal stalk.
玻璃鳗（鳗线）的松果旁器由约400个细胞组成，位于松果体柄与脑室连接处的左侧。一条明显的神经束由约350根纤维组成，起源于松果旁器，并与缰连合呈空间关系地向左缰核延伸。鳗线松果旁器的主要细胞类型是一种直径较小的神经元（感觉神经元），具有非典型纤毛（9×2 + 0，或很少为8×2 + 0类型）。松果旁器缺乏发育良好的光感受器外段，且未明确观察到室管膜类型的间质细胞。神经细胞的轴突形成离开松果旁器的神经束。鳗线的松果体本身由具有发育良好外段的光感受器细胞、室管膜类型的间质细胞和神经节细胞组成。后者的轴突形成松果体束，离开松果体并与连合下器紧密接触，向后连合延伸。松果体柄的近端仅含有少数光感受器细胞，其外段比松果体和松果体柄的远端发育程度低。
