共查询到17条相似文献,搜索用时 62 毫秒
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取已帮血管单注射的中国水蛇头部标本浸于10%HNO3中12小时,剥去脑颅各骨,可看到左右脑动脉之间有很多交通支相连,令左颈总动态血液通过这些交通支达到右侧脑部以及右侧头部各组织器官。脑动脉另一个特点是具有中脑动脉环。 相似文献
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在双目解剖显微镜下观察 24 个经福尔马林固定的中国水蛇 ( Enhydris chinensis) 心脏。它由 1 个静脉窦, 2个心房和2 个心室组成, 但心室分隔不完全。除肺静脉孔外其余孔道均具瓣膜, 肺动脉口、左右体动脉口处各有一对半月瓣。左、右房室孔各有一瓣膜, 但2 瓣在中线上合二为一, 呈帽状。心房表面可见一矢状纵沟, 但非左、右心房的分界线, 房间隔位于沟的左侧, 故右心房较大。心房壁由膜性层和肌性小梁层组成, 所有肌纤维均起止于环绕五大孔裂的结缔组织纤维环上。 相似文献
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中国水蛇消化,呼吸,循环和泄殖系统解剖 总被引:1,自引:1,他引:1
本文报道中国水蛇的消化、呼吸、循环、泄殖等系统的整体解剖。其中、雌性泄殖腔在生殖季节有明显变化,表明它可能是原始阴道雏型。 相似文献
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徐淑娴等(1998)曾经指出:蛇类喉门的两侧壁由杓状软骨构成,控制杓状软骨运动的3对肌肉是喉门开肌、喉门闭肌和环杓侧肌。笔者接着前文,分析前述肌肉的生理功能及其在蛇类喉门启闭运动中的力学现象。1 喉门开肌、喉门闭肌和环杓侧肌的位置与作用喉门开肌位于喉门外侧(图1:A、B),起于第1~5个气管环的侧面及腹面,止于杓状软骨外缘(即侧沟缘),其拉力(F1)方向朝外朝后,作用是令杓状软骨摆向外,开喉门。喉门闭肌覆盖在杓状软骨背面,起于环状背突中线,也止于杓状软骨外缘,止点排列在喉门开肌止点的背方,其拉力(F2)方向朝内朝后,作用是令杓状… 相似文献
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Some snakes have two circumorbital ossifications that in the current literature are usually referred to as the postorbital and supraorbital. We review the arguments that have been proposed to justify this interpretation and provide counter‐arguments that reject those conjectures of primary homology based on the observation of 32 species of lizards and 81 species of snakes (both extant and fossil). We present similarity arguments, both topological and structural, for reinterpretation of the primary homologies of the dorsal and posterior orbital ossifications of snakes. Applying the test of similarity, we conclude that the posterior orbital ossification of snakes is topologically consistent as the homolog of the lacertilian jugal, and that the dorsal orbital ossification present in some snakes (e.g., pythons, Loxocemus, and Calabaria) is the homolog of the lacertilian postfrontal. We therefore propose that the terms postorbital and supraorbital should be abandoned as reference language for the circumorbital bones of snakes, and be replaced with the terms jugal and postfrontal, respectively. The primary homology claim for the snake “postorbital” fails the test of similarity, while the term “supraorbital” is an unnecessary and inaccurate application of the concept of a neomorphic ossification, for an element that passes the test of similarity as a postfrontal. This reinterpretation of the circumorbital bones of snakes is bound to have important repercussions for future phylogenetic analyses and consequently for our understanding of the origin and evolution of snakes. J. Morphol. 274:973–986, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
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The Cranial Osteology Of The Middle Triassic Ichthyosaur Contectopalatus From Germany 总被引:2,自引:0,他引:2
A new partial skull of the Middle Triassic ichthyosaur Contectopalatus atavus allows many new osteological observations and makes the referral of several additional specimens, including lower jaw material, possible. This aids very much in the understanding of the anatomy of this highly derived mixosaurid species. The lectotype of Ichthyosaurus atavus is shown to be diagnostic and the recent proposal of a neotype is unnecessary. Contectopalatus shows thecodont dentition in all parts of the jaws. The teeth are labyrinthodont at their bases. Some specimens, which are interpreted as very late ontogenetic stages of C. atavus , indicate that Contectopalatus grew very large, reaching four to five times the size of other mixosaurids. Mixosaurid taxonomy is reviewed. Three valid genera can be included in a monophyletic Mixosauridae: Mixosaurus (including M. cornalianus and M. kuhnschnyderi ), Phalarodon Contectopalatus (monotypic). The mixosaurids are the sister group to the remaining ichthyosaurs, apart from the Lower Triassic forms. The status of the Omphalosauridae remains unresolved, but they are not closely related to the mixosaurids, because the durophagous dentition was acquired convergently in the two groups. 相似文献
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We report on and name two new taxa of basal crocodylomorph archosaurs from the Lower Jurassic, Litargosuchus leptorhynchus gen. et sp. nov. , from the upper Elliot Formation (Stormberg Group) of South Africa, and Kayentasuchus walkeri gen. et sp. nov. , from the Kayenta Formation (Glen Canyon Group) of Arizona, USA. Examination of this material led to a reconsideration of basal crocodylomorph interrelationships. A phylogenetic analysis found no support for the monophyly of Sphenosuchia. © 2002 The Linnean Society of London. Zoological Journal of the Linnean Society , 2002, 136 , 77–95. 相似文献
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石蒜属12种植物叶片比较解剖学研究 总被引:2,自引:0,他引:2
对石蒜属(Lycoris Herb.)12种植物叶片的比较解剖学研究表明:(1)石蒜属植物叶片横切面的端部、中部及基部的轮廓基本呈浅“W”或“V”字型,有些种的表皮细胞上具有明显的尖刺状乳突;(2)石蒜属植物均为异面叶,叶肉组织有一定的栅栏组织和海绵组织分化,但二者的厚度、叶肉中所占比例及栅栏组织的细胞层数在种间有一定的差异;(3)海绵组织发达、具有大而明显的薄壁细胞或细胞裂溶后形成空腔(分泌腔或气腔);(4)叶片中维管束数目大多为奇数,叶脉维管束鞘由薄壁细胞组成;(5)石蒜属植物横切面上叶缘的形状分为圆弧形和楔形两种类型。石蒜属植物叶的解剖结构具有许多相似特征;同时又具有一定的种间差异,可为石蒜属槽物的种间关系和开发利用提供有价值的信息。 相似文献
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安徽黄精属植物叶片的比较解剖学 总被引:5,自引:1,他引:5
对安徽黄精属(PolygonatumMill.)7种植物的叶片进行了比较解剖学研究。结果表明:(1)7种黄精属植物叶肉细胞中普遍存在含针晶束的异细胞,其数量多少存在种间差异;(2)除玉竹(P.odoratum)的下表皮外,叶表皮均无表皮毛的存在;(3)仅下表皮有气孔器分布,除湖北黄精(P.ganlandeianens)既有单个散布也有2个或3个聚集后随机散布外,均为单个随机散布在下表皮上;(4)叶片无栅栏组织和海绵组织的分化,除湖北黄精和安徽黄精(P.anhuiense)的叶片有不显著的栅栏组织和海绵组织的分化;(5)气孔器的某些特征,如气孔器大小、气孔器分布、气孔器类型等特征以及表皮细胞形状和垂周壁式样在种间有一定的差异。上述特征为黄精属植物种的划分及系统演化关系的探讨提供实验证据。 相似文献