摘要：

The patterns of complexity of the male and female sexual openings in Brachyura, which have been the source of uncertainties and conflicting opinions, are documented, together with a study of the morphologies of the coxal and sternal gonopores in both sexes, penises, spermathecae, and gonopods. The vulvae, male gonopores and penises are described among selected taxa of Eubrachyura, and their function and evolution examined in the context of a wide variety of mating behaviours. The location of female and male gonopores, the condition of the penis (coxal and sternal openings and modalities of protection), and related configurations of thoracic sternites 7 and 8, which are modified by the intercalation of a wide sternal part (thoracic sternites 7 and 8) during carcinisation, show evidence of deep homology. They represent taxonomic criteria at all ranks of the family-series and may be used to test lineages. Of particular significance are the consequences of the posterior expansion of the thoracic sternum, which influences the condition, shape, and sclerotisation of the penis, and its emergence from coxal (heterotreme) to coxo-sternal, which is actually still coxal (heterotreme), in contrast to a sternal emergence (thoracotreme). The heterotreme-thoracotreme distinction results from two different trajectories of the vas deferens and its ejaculatory duct via the P5 coxa (Heterotremata) or through the thoracic sternum (Thoracotremata). Dissections of males of several families have demonstrated that this major difference not only affects the external surface (perforation of the coxa or the sternum by the ejaculatory duct) but also the internal anatomy. There is no evidence for an ejaculatory duct passing through the articular membrane between the P5 coxa and the thoracic sternum in any Brachyura, even when the sternal male gonopore is very close to the P5 coxa. Trends towards the coxo-sternal condition are exemplified by multistate characters, varying from a shallow depression to a long groove along expanded sternites 7 and 8, and ultimately their complete, extended junction typifying the most derived coxo-sternal condition. The coxo-sternal condition is indicative of a long evolutionary history, as evidenced by the presence of multistate characters (e.g., Dorippidae, Goneplacoidea) or by a single, well-established condition (e.g., Chasmocarcinidae, Ethusidae, Panopeidae Eucratopsinae, Rhizopidae, Scalopidiidae). The penial area proves to be an essential diagnostic feature in Brachyura, with a value comparable to that of the gonopods. Penis protection is ubiquitous in Brachyura irrespective of length, and several modalities of protection prevail, which necessitate different modifications of associated structures. A long penis in a gutter developed from a partial invagination of sternite 8 induces the formation of a new "suture" at the same level as the preceding suture 6/7. Such a "supplementary suture 7/8" exists among unrelated heterotreme families (e.g., Ethusidae, Panopeidae Eucratopsinae, Pseudorhombilidae, Rhizopidae). A fully protected penis, concealed in a groove within a complete invagination of sternite 8 in the form of two contiguous plates, evolved independently (homoplasy) in Palicoidea and Chasmocarcinidae (Goneplacoidea), with sternite 8 present as a single plate in females. In condylar protection, described for the first time and occurring in several heterotreme families, the penis emerges from the extremity of the P5 coxo-sternal condyle or from its anterior border instead of from the coxa itself. A penis precisely lodged in a small excavation on sternite 8, which is lined by a row of stiff setae, is unique to Brachyura, and represents a new synapomorphy of the Homoloidea. Five modalities of penis protection are recognised in Podotremata, eight in Eubrachyura (six in Heterotremata and two in Thoracotremata). Special attention has been paid to Dorippoidea (Dorippidae and Ethusidae), which shows transformation series from coxal to coxo-sternal conditions. The coxo-sternal condition is not an intermediate towards th

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