Kenny G C, Scheelings F T
Cell Tissue Res. 1979 May 18;198(2):309-24. doi: 10.1007/BF00232013.
A survey has been made of the pineal region of the brain of 11 species of marsupials belonging to 5 families and a species from both families of monotremes. The results show that the pineal body of non-eutherian mammals, although well-defined in all species, has a very varied morphology. Three types of pineal recess occur: (i) a pineal recess in sensu stricto, (ii) an intercommissural pineal recess, and (iii) an infrapineal recess. The existence of nerve fibres which pass through the pineal body and form a spatial link between the habenular and posterior commissures, has been demonstrated in marsupials and monotremes. It is also likely that these animals as well as eutherian mammals possess a nervus conarii. Nerve cells are not a constant feature of the non-eutherian pineal body. The subcommissural organ (SCO) is present in all species. It does not exhibit the same degree of morphological variation as the pineal body. Horizontal sections available for 4 species within 3 families of marsupials show it to be composed of a median portion jointed to bilateral protuberances. Large nerve cells occur within the SCO in all marsupial species; they are absent from the monotreme SCO. Tentatively, the relationship of these neurons to the SCO is considered to be merely one of association. The importance of an extended comparative study of this region in non-eutherian mammals in order to add insight into its phylogeny and function is emphasized.
对5个科的11种有袋动物以及两个单孔目科的1个物种的脑松果体区域进行了一项调查。结果表明，非真兽类哺乳动物的松果体虽然在所有物种中都有明确界定，但其形态却非常多样。存在三种类型的松果体隐窝：（i）严格意义上的松果体隐窝，（ii）连合间松果体隐窝，以及（iii）松果体下隐窝。在有袋动物和单孔目动物中已证实存在穿过松果体并在缰连合和后连合之间形成空间联系的神经纤维。这些动物以及真兽类哺乳动物也很可能拥有松果体神经。神经细胞并非非真兽类松果体的恒定特征。所有物种均存在连合下器官（SCO）。它并未表现出与松果体相同程度的形态变异。对3个有袋动物科中的4个物种的水平切片显示，它由与双侧突起相连的中间部分组成。所有有袋动物物种的SCO内均存在大型神经细胞；单孔目动物的SCO中则没有。初步认为，这些神经元与SCO的关系仅仅是一种关联。强调了对非真兽类哺乳动物该区域进行扩展比较研究对于深入了解其系统发育和功能的重要性。
