Rodger J C
Am J Anat. 1982 Mar;163(3):269-82. doi: 10.1002/aja.1001630307.
The present study examines and compares the structure of the testis and its excurrent ducts in a caenolestid and four didelphid marsupials. Of particular interest was the site of sperm pairing in the epididymis and whether this feature, shared by both American marsupial families but not by any Australian marsupial, was associated with changes in the morphology of the duct. In contrast to the testes of most Australian marsupials, except the peramelids (bandicoots), the intertubular space in the American marsupials was filled by Leydig cells (around 20% of testis volume). The opossum testes were unusual compared with those of eutherian mammals in that histological sections of individual seminiferous tubules contained only a single cellular association irrespective of the length of the tubule sectioned. The rete testis, as in the Australian dasyurids (devil, quoll, etc.), was a simple branching duct system that arose deep within the testis and emerged as a single duct at the testicular hilus. This arrangement is completely different from that in Kangaroos and Australian possums, indicating a diversity of rete form in the marsupials similar to that seen in eutherian mammals. The rete emptied into a single, essentially straight, efferent duct that became convoluted towards the epididymis, where it formed a distinct structure adjacent to the caput epididymidis. The efferent ducts were highly variable in diameter and epithelial height, suggesting that the duct was not of uniform character along its length, or that the initial single duct had divided to form ducts of different characters. Sperm pairs were first seen in the proximal cauda epididymis, and their appearance was correlated with changes in the character of the duct and its epithelium. The distal ductus deferens of Caenolestes, in contrast to those of the didelphids and indeed all other marsupials, was a convoluted ampulla-like structure adjacent to the prostate gland. In the other marsupials the only accessory sex glands are a segmented prostate and bulbourethral glands.
本研究考察并比较了一种袋鼹和四种负鼠科有袋类动物的睾丸及其输出管道的结构。特别令人感兴趣的是附睾中精子配对的部位，以及这一为美洲有袋类动物家族所共有、但澳大利亚有袋类动物均不具备的特征，是否与管道形态的变化相关。与大多数澳大利亚有袋类动物（除袋狸科动物外）的睾丸不同，美洲有袋类动物的睾丸间质空间充满了莱迪希细胞（约占睾丸体积的20%）。与真兽类哺乳动物相比，负鼠的睾丸不同寻常之处在于，无论所切取的生精小管段长度如何，单个生精小管的组织学切片中仅含有单一的细胞组合。与澳大利亚袋鼬科动物（袋獾、袋猫等）一样，睾丸网是一个简单的分支管道系统，起源于睾丸深处，在睾丸门处汇合成一条单一管道。这种排列方式与袋鼠和澳大利亚袋貂的完全不同，表明有袋类动物的睾丸网形态具有多样性，类似于真兽类哺乳动物。睾丸网汇入一条单一的、基本笔直的输出小管，该小管在靠近附睾处变得盘曲，在附睾头附近形成一个独特的结构。输出小管的直径和上皮高度变化很大，这表明该管道在其长度上并非具有统一的特征，或者最初的单一管道已经分裂形成了具有不同特征的管道。精子对首先出现在附睾近端尾部，其出现与管道及其上皮特征的变化相关。与负鼠科动物以及实际上所有其他有袋类动物不同，袋鼹的远端输精管是一个与前列腺相邻的盘曲的壶腹样结构。在其他有袋类动物中，唯一的附属性腺是分节的前列腺和尿道球腺。
