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福州近郊分布的渔游蛇睾丸精子发生在１０月达最高峰。全年出现二次雄性激素高峰。肾性节在１０月份达发育高峰,其上皮细胞中的分泌颗粒含糖类、缩醛磷脂、酸性磷酸酶和乳酸脱氢酶,不含酸性粘多糖、碱性磷酸酶、琥珀酸脱氢酶或含量（活性）极低。肾性节的组织变化与睾丸的精子发生活动呈同步性。 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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《四川动物》2005,24(3):330-334
根据野外观察和解剖标本,本文报道蛇亚目、游蛇科、水游蛇亚科中国南方常见优势种铅色水蛇的生物学研究初步结果。1,长度：112号雄蛇全长范围286～466mm,151号雌蛇全长范围306～504mm。海南陵水103号雄蛇最大全长358＋54=412mm,137号雌蛇最大全长443＋61=504mm。2．鳞片的变异：根据299号标本观察,数量恒定无变异的鳞片有：吻鳞（1）,鼻间鳞（1）,前额鳞（2）,额鳞（1）,顶鳞（2）,鼻鳞（每侧1）,颊鳞（每侧1）,眶上鳞（每侧1）,前颞鳞（每侧1）,颏鳞（1）,颔片（2对）,背鳞（19-19-17行）,肛前鳞（完整）;根据鳞片有变异的67号标本观察,可出现变异鳞片的变异范围及其频率：眶前鳞1（1→2,4．5％）,眶后鳞2（2→1,3．0％）,后颞鳞2（2→1．1．5％）,上唇鳞3-2-3（3-1-4,0．75％）,下唇鳞10（9,0．75％;11,2,25％）;腹鳞与尾下鳞则绝对有变异：腹鳞雄性112号变异幅度124～136（平均128．2）,雌性151号变异幅度123～132（平均126．1）,尾下鳞雄性107号变异幅度36～41（平均39．7）对,雌性149号变异幅度31～36（平均33．7）对。3．两代之间变异的消失和出现：两例母蛇的右侧眶前鳞均变异为2,她们的全部仔蛇21号均正常为1;一例母蛇的下唇鳞为正常的10枚,而她的仔蛇6号中有两号分别有一侧或两侧变异为9。4．垂直分布范围：沿海低地到海拔985m。5．栖息环境：各种水域,以静水水域为主,在海南陵水县吊罗山大里乡以灌水后的稻田为主,极少数发现在静水水域或流动缓慢的灌溉渠内。6．摄食和食性：每年4月开始摄食,6月为摄食高峰,9月停止;食物以小形蚌类和蝌蚪为主,其次为小鱼。7．繁殖习性：二级性征主要反映在雄性尾的比例较长,尾下鳞的数目相应较多;二级性比（出生时的性比）接近1：1,三级性比在居群较大的情况下也约为1：1,而在居群较小的情况下统计约为0．5：1;雌性性成熟期（以开始产仔为依据）全长都在350mm以上;解剖28号孕雌得知输卵管卵数3～12（平均6．3）枚;卵在母体内发育进程：解剖41号成熟雄性得知4月卵尚未发育,5月及6月处于发育中或晚期、产仔或已产出,7月基本都已产毕;统计两窝21仔得知初产出仔蛇全长127～139mm,母蛇体长大者其仔蛇亦较长;统计同窝9仔得知初生仔蛇重量2．4～2．5g,平均2．47g。本文是作者早期未发表的工作,现整理供对蛇类有兴趣的青年同行参考。本研究所用全部标本（包括3号雌蛇及其刚产出的仔蛇）均保存在中国科学院成都生物研究所两栖爬行动物标本馆。 相似文献
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自从1762年蚜虫孤雌生殖的现象被描术以后,直到十九世纪初方才证实了枝角类也同样进行这种生殖方法.后来经过Kerlherve氏(1892)与Smith氏(1915)进一步的研究,又确定在这类动物中孤雌生殖与两性生殖相互交替,发生所谓世代交替的现象。通常春、夏、秋三季进行孤雌生殖,雌体所产夏卵,不需要受精,即能发育;孵化出来的都是雌体。 相似文献
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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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电损毁缰核对成年雌性大鼠生殖周期及生育力的影响 总被引：1，自引：1，他引：1
电损毁缰核对成年雌性大鼠生殖周期及生育力的影响马丽娜黄民王绍（白求恩医科大学生理教研室,长春１３００２１）边缘前脑至脑干背侧通路的枢纽—缰核（Ｈａｂｅｎｕｌａ,Ｈｂ）参与生殖功能活动的调节。研究资料表明,蟾蜍Ｈｂ的体积在春季生殖期明显增大;在雌兔的Ｈ... 相似文献
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植物的生殖讲座（八）──植物生殖生物学研究进展陈祖铿（中国科学院植物研究所北京１０００４４）植物生殖生物学是研究植物有性生殖过程的一门分支学科,它涉及性细胞发育、传粉与受精,以及胚胎发生等。从广义讲,可以包括各种形式的营养体无性繁殖和孢子生殖过程。花... 相似文献
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Inbreeding for 6 generations has produced a strain of amelanistic western diamondback rattlesnakes (Crotalus atrox) with extremely variable scalation. Forty-four siblings varying from virtually no body scalation to normal scalation have been produced in the latest generation. Two of the 3 most extreme “scaleless” snakes were stillborn; the third was maintained for > 1 year. Two of 7 snakes with greatly reduced head and body scales have died; however, the remaining 5 are being maintained and appear to be growing and healthy at 5 or 6 years of age. All snakes with reduced body scales have abnormal ventral scutes. Fifteen snakes with predominantly normal body scales have anomalous head scales, head scale patterns, and ventral scutes. One snake has predominantly normal scalation except for aberrant ventrals. A total of 18 Generation VI snakes have been classified as “normal,” although all snakes were not closely examined before disposition. Nine of the more normally scaled generation VI snakes are also being maintained in the laboratory. It is difficult to separate the genetic and environmental components of these phenotypes with existing information; however, it seems apparent that more than a single locus is involved. © 1994 Wiley-Liss, Inc. 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 naso-frontal joint of snakes is described on the basis of high-resolution X-ray computed tomography scans of single individuals of spirit-preserved snake specimens. The suspension of the snout unit from the braincase at the naso-frontal joint shows some broad evolutionary trends among snakes with potential phylogenetic implications, such as sutured or fused medial frontal flanges formed by the medial frontal pillars and the frontal subolfactory processes (in alethinophidians), the restriction of the usually extended dorsoventral contact of the medial nasal flange with the medial frontal flanges to a dorsal or ventral contact (in macrostomatans), and the transfer of the main element of snout suspension from the nasal to the septomaxilla (in colubroids). Some phylogenetic implications of the morphological characters identified in this study are outlined and discussed. 相似文献
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Oviducal sperm storage in the viviparous (lecithotrophic) colubrid snake Seminatrix pygaea was studied by light and electron microscopy. Out of 17 adult snakes examined from May–October, sperm were found in the oviducts of only two specimens. In a preovulatory female sacrificed 14 May, sperm were found in the oviducal lumen and sperm storage tubules (SSTs) of the posterior infundibulum. In a nonvitellogenic female sacrificed 9 June, sperm were found in the lumen and glands of the posterior uterus and anterior vagina, indicating a recent mating. The glands in the posterior infundibulum and vagina were simple or compound tubular, whereas glands in the uterus always were simple tubular. The epithelium of the sperm storage glands was not modified from that lining the rest of the oviduct. The cuboidal or columnar epithelium consisted of alternating ciliated and secretory areas. The secretory product released into the lumen by a merocrine process contained mucoprotein. Lipid droplets also were numerous in the epithelium. Portions of sperm sometimes were embedded in the apical cytoplasm or in secretory material. A carrier matrix containing a mucoid substance, desquamated epithelium, lipids, membranous structures, and possibly phagocytes was found around sperm in the posterior uterus. J. Morphol. 241:1–18, 1999. © 1999 Wiley‐Liss, Inc. 相似文献
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Zbigniew Szyndlar 《Pal?ontologische Zeitschrift》2009,83(1):55-66
The Early/Middle Miocene (European Land Mammal Zone MN5) localities of Sandelzhausen and Rothenstein 13 in southern Germany have yielded remains of about 13 ophidian taxa: Eoanilius sp. (Aniliidae), Bavarioboa ultima (Boidae), “Coluber” sp., ?Telescopus sp., Natrix sp., cf. Natrix sp., cf. “Neonatrix” sp., unidentified “colubrines” and “natricines” (Colubridae), Naja sp., an unidentified elapid (Elapidae), Vipera sp. (“Oriental viper”), Vipera sp. (“aspis complex”) (Viperidae). Both faunas document a transitional phase from those reported from several late Early and Middle Miocene sites of Central and Western Europe. The climates of Sandelzhausen and Rothenstein 13, as indicated by ophidian fossils, were warm, although not tropical or subtropical. 相似文献
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《Journal of Asia》2021,24(3):731-738
The reproduction strategies of invertebrates, oviparity, ovoviviparity and viviparity, always reflect the relationship between individuals and their surroundings. There is plasticity in the reproductive strategies of sarcosaphagous flies as they adjust to rapidly changing circumstances. The transition from oviparity to ovoviviparity or viviparity involves numerous changes in physiology, morphology and immunology. Demonstrating these processes can make the application of entomology work in forensic practice more reliable. This essay reviews means of reproduction in sarcosaphagous flies and identifies related features. It is shown that not only the reproduction traits, such as fast location of carrion, and uncommon number of ovaries and oogenesis, but also some morphological features are related to viviparity. In general, viviparous flies have larger adult bodies but smaller eggs and chorions. Moreover, the length of terminalia and the shape of the vagina also varies among those three modes. Reproductive plasticity is a bridge between the three reproductive modes, and it can greatly influence the inference of the post-mortem interval (PMImin). 相似文献
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日本沼虾生精细胞核的形态变化及其在真虾部Caridea生殖进化中的地位 总被引：14，自引：0，他引：14
应用透射电镜（ＴＥＭ）技术研究了日本沼虾精子发生过程中细胞核的形态变异。生精细胞的核经历了由圆形或椭圆形变为浅碟状的一系列变化过程;其核膜由原来的完整变为不完整,成熟精子仅在精子尾部具有核膜;核内染色质由松散逐渐聚合分化,在成熟精子核内形成了泡状和丝状两种形态的核物质。精子具备泡状和丝状两种核物质是日本沼虾的重要特征之一。精核的形态可以作为十足类甲壳动物的重要分类依据;研究精子发生过程中细胞核的形 相似文献
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In mature male snakes and lizards, a distal portion of the nephron is hypertrophied in relation to its appearance in females and immature males. This sexual segment of the male kidney apparently provides seminal fluid that is mixed with sperm and released into the female cloaca during copulation. In this article, we provide the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea. Previous workers have indicated that the sexual segment is secretory only when the testes are spermatogenically active. The sexual segment of the kidney in S. pygaea does not go through an extended period of inactivity but does show a cycle of synthesis and secretion that can be related to the spermatogenic cycle and mating activity. We show that synthesis of secretory product is initiated with the onset of spermatogenic activity in the spring and culminates with completion of spermiation in the fall. Secretion of the product, however, occurs in a premating period in March when the testes are inactive. Secretion during this premating period is probably necessary to provide time for the passage of the products down the ureter in order to mix with sperm during mating later in spring. 相似文献
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多疣壁虎的繁殖生态研究 总被引：10，自引：3，他引：10
多疣壁虎(Gekko japonicus)是一种季节性繁殖的爬行动物,性腺活动状态在不同的季节有显著的差异。成年雌体在冬眠结束后的4月初卵巢开始增大,野外产卵期一般在5月下旬至8月上旬。一个繁殖期平均产卵1.8窝,每窝恒定两枚。每窝卵重与个体大小之间存在着显著的正相关,大个体的产卵频率亦较高。雄体的精巢重量和大小的月间差异显著,但变化不及雌体的卵巢显著。雌体的繁殖期可以被环境温度所改变。繁殖效力用每窝卵干、湿重及能值与雌体干、湿重及能值的比值估算。 相似文献