APPLICATION OF CLUSTER ANALYSIS TO THE TAXONOMY OF ORDER AND SUBORDER OF THE TRILOBITA

In the present paper, in accordance with the exoskeleton structure, the method of Q-mode cluster analysis is used for a taxonomic study of 17 orders (suborders) of the Tritobita that was established or adopted by H. J. Harrington (1959), J. Bergstrm (1973), and R. A. Fortey and R. M. Owens (1975). The author suggests that the Trilobita be subdivided into 9 orders and 14 suborders, i. e. order Agnostida Kobayashi, 1935 (suborder Agnostina Salter, 1864 and suborder Eodiscina Kobayashi, 1939), order Redlichiida Richter, 1933 (suborder Redlichiina Richter, 1933, suborder Bathynotina Lochman-Balk, 1959 and suborder Olenellina Resser, 1938), order Corynexochida Kobayashi, 1935, order Ptychopariida Swinnerton, 1915 (suborder Ptychopariina Richter, 1933, suborder Proetina Fortey & Owens, 1975, nom. transl, ex Proetida Fortey & Owens, 1975 and suborder Calymenina Swinnerton, 1915, emended herein), order Illaenida Jaanusson, 1959 (suborder Illaenina Jaanuson, 1959 and suborder Asaphina Salter, 1864, emended herei     

四川老鹳草属植物的花粉形态及其系统学意义

用光学显微镜和扫描电镜对分布在四川的８组３０种老鹳草属植物进行了花粉形态观察，并结合植物的外部形态特征研究了它们的一些系统学意义。     

多毛纲(Polychaeta)动物系统学的研究进展

多毛纲动物以海洋底栖分布为主,在长期的进化过程中,产生了形形色色适应不同环境的形态特征和生活史策略.对其系统学的研究,有助于理解自然界生物多样性的保持机制及其在生物系统进化过程中所发挥的作用.从目前的研究结果来看,多毛纲动物为并系发生,但它们在环节动物系统发生树中的基部类群以及大部分并系群之间的相互关系仍有待确定.今后应该增加各类群有代表性的物种的取样数量,开展形态学特征、生活史策略以及分子遗传标记的综合研究,以期完善多毛纲动物的系统学.     

Systematics on fission fragment mass distribution of neutron induced 235U fission

Based on the neutron induced fission fragment mass distribution data up to neutron energy 20 MeV measured with the double kinetic energy method (KEM) and the radio active method (RAM), the systematics of fission fragment mass distribution was investigated by using 5 Gaussian model and the systematics parameters were obtained by fitting the experimental data. With the systematics, the yields of any mass A and at any energy in the region from 0 to 20 MeV of neutron energy can be calculated. The calculated results could well reproduce the experimental data measured with KEM, but show some systematical deviation from the data measured by RAM, which reflects some systematical deviations between the two kinds of measured data.The error of systematics yield was calculated in an exact error transformation way, including from the error of the experimental yield data to the error of the discrete parameters, then to the systematics parameters,and at last to the yield calculated with systematics.     

（n，t）反应截面的系统学计算

研究了中等和重质量核的１４ＭｅＶ（ｎ，ｔ）反应截面的系统学特性．在考虑奇偶效应的基础上给出了反应截面的系统学公式和经验参数，利用这套参数计算了一些核素的反应截面，结果与测量值符合较好．并讨论了可能的反应机制和Ｑ值效应．     

Sm-Nd isotope dating of hydrothermal calcites from the Xikuangshan antimony deposit,Central Hunan

The research on Samarium-Neodymium isotope systematics of hydrothermal calcites from the Xikuangshan antimony deposit, Central Hunan, places precise timing constraints on the Sb mineralization in this area. It is revealed that the Xikuangshan deposit formed during the late Jurassic-early Cretaceous Period, the early- and latestage mineralization took place at (155.5± 1.1) Ma and (124.1±3.7) Ma, respectively. The accurate age determination of mineralization is very crucial for revealing the super-enrichment mechanism of the element Sb at the Xikuangshan mine, and lays some foundations for the further understandings of its ore genesis and mineralization mechanism.     

囊壳在囊裸藻系统分类中的作用

根据作者十几年的工作积累，结合前人的工作，从囊壳的形状、表面特征、领的形态、颜色和元素组成等方面论述了这些特征的变化，以及在系统分类中的作用，认为囊壳在系统分类中的作用是非常重要的，在囊裸藻属自然分类系统建立时，既要依照原生质体的特征，也要充分参考囊壳的特征。     

6种瓢虫的RAPD分析及在分类上应用的研究

利用随机引物分别对6种瓢虫的DNA进行了聚合酶链式反应（RAPD－PCR）的实验。结果显示，用相同引物扩增不同种瓢虫的基因组DNA，扩增产物多态性DNA片段的数目是不同的；两种不同引物的扩增产物中，各自呈现出种、属的特异性片段，其可用于种、属的鉴别；聚类图显示了种、属之间亲缘关系的远近程度，并与形态学分类结果相一致。实验分析还发现：七星瓢虫不同个体间多态性DNA特有带较多，遗传较稳定；龟纹瓢虫与之相比，不同个体间多态性DNA的特有带较少，变异程度较大。     

<Emphasis Type="Italic">X</Emphasis>-Trees and Weighted Quartet Systems

In this note, we consider a finite set X and maps W from the set $ \mathcal{S}_{2|2} (X) $ of all 2, 2- splits of X into $ \mathbb{R}_{\geq 0} $. We show that such a map W is induced, in a canonical way, by a binary X-tree for which a positive length $ \mathcal{l} (e) $ is associated to every inner edge e if and only if (i) exactly two of the three numbers W(ab|cd),W(ac|bd), and W(ad|cb) vanish, for any four distinct elements a, b, c, d in X, (ii) $ a \neq d \quad\mathrm{and}\quad W (ab|xc) + W(ax|cd) = W(ab|cd) $ holds for all a, b, c, d, x in X with #{a, b, c, x} = #{b, c, d, x} = 4 and $ W(ab|cx),W(ax|cd) $ > 0, and (iii) $ W (ab|uv) \geq \quad \mathrm{min} (W(ab|uw), W(ab|vw)) $ holds for any five distinct elements a, b, u, v, w in X. Possible generalizations regarding arbitrary $ \mathbb{R} $-trees and applications regarding tree-reconstruction algorithms are indicated.AMS Subject Classification: 05C05, 92D15, 92B05.     

Is the PhyloCode better than Linnaean system?—— New development and debate on biologi-cal nomenclatural issues

The Linnaean system provides ultimate means governing biological nomenclature and classification.With series of modification,this system has admirably served biological sciences for some 250 years.The new PhyloCode,however,advocates the phylogenetic nomenclature that radically alternates the current nomenclatureal rules.The new proposals upset many systematic biologists and have provoked hot debate on nomenclatural issues.Binomial nomenclature and hierarchical classification are the key components of the Linnaean system.Proposed abandonment of these in the PhyloCode is widely criticized for it would not help to promote systematics but create chaos.It is not the Linnaean system but the phylogenetic nomenclature that should be abandoned.