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HENRIK ENGHOFF WOLFGANG DOHLE J. GORDON BLOWER 《Zoological Journal of the Linnean Society》1993,109(2):103-234
A review of the postembryonic development of millipedes (Diplopoda) is given, based mainly on published information. Original observations are, however, also included. Millipedes hatching from the pupoid usually have three pairs of legs; during their postembryonic growth they acquire more segments and more legs. This process is known as anamorphosis. Three types of anamorphosis are recognized. In euanamorphosis, every moult is accompanied by addition of new segments, even after the attainment of sexual maturity. In hemianamorphosis, the addition of new segments goes on until a certain stadium, and further moults take place without addition of segments. In teloanamorphosis, the addition of segments stops at a certain stadium (the adult, and ultimate, stadium) after which no further moults occur. Available information on anamorphosis in each of the millipede orders is reviewed. General patterns are emphasized, but variations are also considered in detail. It is shown that the so-called ‘law of anamorphosis’ is valid only for the ‘ring-forming’ millipedes (Merocheta and Juliformia) in which tergites, pleurites, and sternites of each diplosegment are firmly fused into a complete ‘ring’, and for some other forms (Polyzoniida, Chordeumatida), where there is a constant relationship between rings and legs. The chapter on the order Julida is particularly detailed and includes discussions of patterns in the variation and a section on periodomorphosis. The general chapter on developmental patterns includes inter alia an interpretation of the variations in millipede anamorphosis in terms of the ‘biometabolic modi’ of Remane. The hypothetical ancestral millipede is shown to have developed by hemianamorphosis. Euanamorphosis was acquired by the ancestral species of Helminthomorpha. Within this clade, Chordeumatida and Merocheta have secondarily become teloanamorphic, whereas some Juliformia seem to have returned to hemianamorphosis. The contrasting principles of elongation and contraction, subject of much debate among diplopodologists, are shown both to have played a role in the course of millipede evolution. 相似文献
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Regional growth patterns in the hypocotyls of etiolated and green cress seedlings in light and darkness 总被引:3,自引:3,他引:0
Abstract. A system is described whereby seedling development can be analysed in terms of growth rates of specific 1 mm regions of the hypocotyl. The technique involves time-lapse photography of marked hypocotyls in a specially designed chamber which accommodates seedlings in various orientations with respect to gravity, and under irradiation regimes differing in light quality, quantity and direction. The results of a preliminary study of the upward growth of etiolated or green cress seedlings in darkness or overhead while light are reported. Highest growth rates in etiolated seedlings were observed in zones in the upper one-third of ihe hypocotyl. In green seedlings, growth was more prominent within the subapical zones. Light further restricted growth of the median and basal zones in both types of seedling. However, in their immediate responses to the onset of irradiation, green and etiolated seedlings differed markedly. In etiolated seedlings, recovery of growth at the apex was accompanied by the development of inhibition in the median-basal regions; green seedlings showed a transient inhibition of growth in the apical zone together with a strong immediate inhibition in the median-basal regions. 相似文献
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Structure and Function of the Adrenal Gland of Fishes 总被引:1,自引:0,他引:1
The structure and distribution of the adrenal gland in fishesis reviewed. Studies on the in vitro and in vivo biosynthesisof adrenocortical steroids and their occurrence in the bloodof fishes are evaluated in the light of modern techniques forthe identification and quantification of steroids. There followsan appraisal of some literature dealing with the adrenocorticalcontrol of intermediary metabolism and ion transport in fishes. 相似文献