孤峰组最底部的牙形刺动物群

在孤峰组底部发现了包括Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ在内的牙形刺动物群。Ｇｏｎｄｏｌｅｌｌａ ｓｅｒｒａｔａ Ｃｌａｒｋ ｅｔ Ｅｔｈｉｎｇｔｏｎ,１９６２是Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ（Ｊｉｎ,１９６０）的同义名,Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａｎｋｉｎｇｅｎｓｉｓ已被北美学者推荐为瓜达洛坪统底界的标志化石。因Ｍｅｓｏｇｏｎｄｏｌｅｌｌａ ｎａ     

The distribution of alpha-melanocyte stimulating hormone (alpha-MSH) in the central nervous system of the rat: an immunohistochemical study. II. Lower brain stem

The distribution of immunoreactive alpha-melanocyte stimulating hormone (alpha-MSHI) in the rat lower brain stem was examined by indirect immunofluorescence or peroxidase- anti-peroxidase immunohistochemical method using an antiserum against synthetic alpha-MSH. The results confirmed the presence of alpha-MSHI fibers in the midbrain central gray matter and parabrachial area, and demonstrated a much more extensive distribution of these fibers in various parts of the lower brain stem areas previously thought not contain alpha-MSHI fibers. In addition, the commissural nucleus was identified as a new alpha-MSHI neurons-containing site. No alpha-MSHI neurons were seen in other regions of the rat lower brain stem.     

鄂东南早白垩世灵乡群孢粉组合

本文根据从大冶灵乡-陈重山剖面的中部、灵乡狮子山东侧采坑和鄂城太和1孔的相当层位中所获得的孢粉组合(共67属120余种,其中新种9个,新联合2个),认为灵乡群孢粉组合属于 Classopollis、Psophosphaera-Cicatricosisporites、Schizaeoisporites-没有或极个别的出现被子植物花粉的组合类型,其地质时代应为早白垩世早期-中期(凡兰吟期-巴列姆期)。并推测鄂东南地区当时的气候属于偏干旱的热带-亚热带型。     

新型有原始肢突胴甲鱼的发现及胴甲鱼早期演化的初步探讨

本文记述的曲靖始突鱼(Procondylolepis qujingensis gen.et sp.nov.)是近几年在云南曲靖早泥盆世地层中发现的有肢突胴甲鱼一原始类型。它和已知胴甲鱼(包括早泥盆世无肢突的和中、晚泥盆世有“盔”状肢突的)不同的最大特点是在其肩带与胸鳍相接的肩关节处有原始的肢突和简单的关节窝;胸鳍甲近端的关节区很小。它展现出胴甲鱼类这一高度特化、长期使人迷惑不解的肢突,在胴甲鱼演化史上发展变化的梗概,填补了肢突从无到有中间的缺环,使人了解到胸鳍的具体结构。文中主要根据肢突的有无和特化程度等,对胴甲鱼早期演化史作了初步探讨,将胴甲鱼分为无肢突超目(Abrachicondylia)和有肢突超目(Brachicondylia)两大部分。始突鱼则代表有肢突超目一早期成员。     

Analytical treatment of pattern formation in the Gierer-Meinhardt model of morphogenesis

Summary We first perform a linear stability analysis of the Gierer-Meinhardt model to determine the critical parameters where the homogeneous distribution of activator and inhibitor concentrations becomes unstable. There are two kinds of instabilities, namely, one leading to spatial patterns and another one leading to temporal oscillations. Focussing our attention on spatial pattern formation we solve the corresponding nonlinear equations by means of our previously introduced method of generalized Ginzburg-Landau equations. We explicitly consider the two-dimensional case and find both rolls and hexagon-like structures. The impact of different boundary conditions on the resulting patterns is also discussed. The occurrence of the new patterns has all the features of nonequilibrium phase transitions.     

Ultrastructural changes in muscle mitochondria in situ,including the apparent development of internal septa,associated with the uptake and release of calcium

Treatment of mammalian muscle with the divalent cation ionophore A23187 causes the release of Ca2+ from the sarcoplasmic reticulum and allows the ultrastructural changes of the mitochondria during Ca2+-uptake to be demonstrated in situ. Electron micrographs reveal that the mitochondria swell dramatically during uptake, before contracting again when the accumulated Ca2+ is released once more into the cytoplasm. When maximally swollen, the mitochondria are apparently subdivided and internal "septa" are formed. The ultrastructural details concerning these internal membranous structures are shown in detail and their significance is discussed.     

A reappraisal of the Palaeopantopoda with description of a species from the Jurassic

The Devonian fossil Palaeoisopus appears, in the light of recent evidence from newly found specimens, to be much nearer extant pycnogonids than previously surmised. The fossil record of the Pycnogonida is extended to the Jurassic on the basis of a long overlooked Solenhofen example. Most of the specimens ascribed to the common Solenhofen Phalangites cannot be pycnogonids, but it is possible that we are dealing with a complex of superficially similar fossils. A revision of the classification of the fossil pycnogonids (Order Palaeopantopoda) is suggested in the light of this new material.     

A NEW GENUS OF CAPRINI (BOVIDAE, ARTIODACTYLA) FROM UPPER PLIOCENE OF YUSHE, SHANSI

<正> In the present paper a new caprine, Sinocapra minor gen. et sp. nov. is erected on the basis of several horn cores. The type specimen was collected by the Sino-American Palaeontology Expedition from the Upper Pliocene, Mazegou Formation, of Yunzhu Subbasin, Yushe Basin, Shansi province in 1988. All the other ones referred to the new genus were described and identified by Teilhard de Chardin and Trassaert (1938, p. 53, fig. 46) as Antilope gen. et sp. indet. They also came from Zhaozhuang, Yunzhu Subbasin and it is likely that they might be gathered from the same Formation as the type specimen judging by the yellow sandy clay filling into the horn cores. Magnetostratigraphic studies by Prof. N. Opdyke of the Yunzhu Subbasin indicates that this stratigraphic interval only includes the Gauss one, approximately 3.4 to 2.47 Ma. Accounts of the biostratigraphy and dating of Yunzhu Subbasin are giyen by Dr. R. H. Tedford and Dr. Z. Qiu in another paper.