共查询到20条相似文献,搜索用时 15 毫秒
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F. E. Fremantle 《BMJ (Clinical research ed.)》1908,1(2453):53-54
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Heike Wägele 《Polar Biology》1989,9(4):235-243
Summary Rich material of the genus Tritoniella (Opisthobranchia, Nudibranchia) from the Atlantic sector of the Antarctic Ocean demonstrates that the features of the internal anatomy are fairly constant in contrast to those of the external morphology and the cuticularized structures (radula and jaws). There are specimens intermediate between the two known species of the genus: T. belli Eliot, 1907 and T. sinuata Eliot, 1907. These specimens either show a combination of features characteristic for T. belli and T. sinuata, or of features which lie in between. Therefore T. sinuata is considered to be synonymous with T. belli. The monotypic genus Tritoniella has a circumpolar distribution with an extension of its range to the Subantarctic (South Georgia). 相似文献
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A cytogenetic study of Dictyocaulus arnfieldi was made for the first time. The diploid chromosome number was 2n = 11 for males and 2n = 12 for females; there was an XO/XX sex determinism mechanism. Diplotene stage showed bivalents with 3, 2 or 1 chiasmata. The possible differences in the evolution of D. arnfieldi and Dictyocaulus filaria are discussed. 相似文献
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