TEMPERATURE COEFFICIENT OF THE ACTION OF β-RAYS UPON THE EGG OF NEREIS

The temperature coefficient of the action of β-rays from radium upon the egg of Nereis lies between 1.1 and 1.2. This is of a magnitude characteristic of photochemical reactions.     

METAMORPHOSIS OF THE LARVA OF THE POLYCHAETE ARENICOLA CRISTATA. MORPHOLOGY OF THE ‘HOUR-GLASS’ STAGE

The constricted ‘waist’ of the metamorphosing larva of the polychaete Arenicola cristata is described, using light and electron microscopy. The constriction is shown to be the consequence of the discharge and collapse of a post-trochal ring of epithelial cells which remain as functional components of the post-metamorphic juvenile. Morphological differentiation of neuro-effector and interneuronal contacts is initiated at this time. Muscular and neural changes are discussed in terms of their role in effecting metamorphosis.     

A STUDY OF INFLATION OF THE LUNGS OF THE NEWBORN—A Preliminary Report

There seems to be no reasonable doubt that the lungs in a newborn expand progressively during the first few days of life. Some degree of atelectasis seems to be perfectly normal. This is indicated by a number of roentgenographic studies (including those here reported); by the reported findings of pathologists; by the fact that in experimental animals the lungs inflated very unevenly; and by the fact that aeration of only a portion of the lung is needed for complete oxygenation of the blood. The relation of atelectasis to neonatal death is not entirely clear and is probably not always the same. The infant may die from other causes before the lungs are fully expanded. Atelectasis may develop secondarily to other debilitating conditions. The frequent coincidence of prematurity and extensive atelectasis is impressive. It may be that the lungs are so incompletely formed that they cannot expand. On the other hand, atelectasis and massive collapse in the adult is a serious condition and there seems to be no good reason to suppose that this cannot also occur in infants and be serious per se.The air pressures found necessary to expand the lungs in rabbit fetuses were found to be about ten times what adult humans use in quiet respiration and were of about the same magnitude as the pressures found necessary to expand the lungs of stillborn humans. An attempt to produce atelectasis in newborn rabbits by chilling was most inconclusive. Atelectasis did develop in three of 15 animals used in the experiment, but the relation to chilling was not at all clear.     

ON THE LARVAE OF THE CHINESE SPECIES OF THE SUBFAMILY CHRYSOMYINAE(DIPT.CALLIPHORIDAE)

In this paper, the author described the larvae of Chinese Chrysomyine flies. All larval specimens of the seven species studied in this paper were reared in the laboratory. The 7 species of Chrysomyinae are as follows: Chrysomya megacephala (Fab., 1794). Fig.1. Ch. pinguis (Wlk., 1858). Ch. bezziana Vill., 1914, Fig.2. Ch. defixa (Wlk., 1857), Fig.3. Achaetandrus rufifacies (Macq., 1842). Fig. 4a.b. Ach. villeneuvii (Patton. 1922). Fig. 4b. (right 5, 8.) Ceylonomyia nigripes (Aubt., 1932). Fig. 5. The larvae of following species are described for the first time.     

ON THE LARVAE OF THE CHINESE SPECIES OF THE TRIBE LUCILIINI (DIPT.CALLIPHORIDAE)

The present paper deals with the larvae of 10 species of Luciliini from China. The 10 species of Luciliini are as follows: Hypopygiopais infumata (Bigot, 1877), Fig. 1. Hemipyrellia ligurriens (Wied., 1830), Fig. 2. Lucilia sericata (Meig., 1826), Fig. 3. L. cuprina (Wied., 1830), Fig. 4. L. illustris (Meig., 1826), Fig. 5. L. caesar (L., 1758), Fig. 6. L. porphyrina (Walk., 1857), Fig. 7. L. ampullacea laoshanensis Quo, 1952, Fig. 8.     

THE 2ND CONGRESS OF THE PALEOBOTANICAL SOCIETY OF PSC HELD IN NANJING

The 2nd Congress of the Paleobotanical Society of Palaeontological Society and the Paleobolanical symposium (1987) held from November 24th to 27th at Nanjing, Jiangsu. Present at the meeting were 86 Chinese paleobotanists and several students from research institutes, universities, colleges, natural historical museums and geological, coal- and petroleum-prospecting parties.     

ON THE EVOLUTION OF MEGACERINES

<正> The megacerine deer (the tribe Megacerini of the subfamily Cervinae) is a rather ancient extinct group, known from the end of the Miocene, The tribe comprises 8 genera: Megaceros Owen, 1844, Sinomegaceros Dietrich, 1933, Praemegaceros Portis, 1920, Praedama Portis, 1920, Arvernoceros Heintz, 1970, Neomegaloceros Korotkevitch, 1971, Orchonoceros Vislobokova, 1979 and Praesinomegaceros Vislobokova, 1983. The Pleistocene history of megacerines is much studied regarding the evolutionary stage of these deer. Almost all students recognize the existence of two branches of megacerines in the Pleistocene of Europe: one of these connected with Megaceros giganteus (Blumenbach, 1803) and the other with Praemegaceros verticornis (Dawkins, 1872), although the estimations of the systematic range of these cervids are different (Azzaroli,     

THE USE OF MULTIPLE REGRESSION ANALYSIS FOR ESTIMATING THE ACTION PATTERN OF CELLULASE FRACTIONS IN HYDROLYSIS OF CELLULOSE

A comprehensive regression model was developed for estimating theaction pattern of three cellulase fractions (β-1,4-glucan cellobiohydrolase,endo-glucanase and cellobiase)in hydrolysis of cellulose.The effect of stru-cture feature of cellulose on hydrolysis can also be evaluated by using thismodel.The results suggested that this technique was suitable for estimatingthe action pattern of cellulase fractions in cellulose hydrolysis,especiallyin quantitative eluciation of the effect of each fraction,alone or in combin-ation of which.     

THE RELATIVE PHYSIOLOGICAL EFFECTS OF β- AND γ-RAYS UPON THE EGG OF NEREIS

When Nereis eggs are exposed to radiations from a tube of radium emanation, the walls of which absorb all the α-rays, the resulting physiological change is produced by rays having a coefficient of absorption of the order of 23.9 cm.^–1 This fact indicates that the physiological effect is due almost exclusively to β-rays. The γ-rays alone can produce the reaction. To produce equivalent physiological effects exposure to γ-rays alone must be approximately 60 times as long as exposure to β- and γ-rays together.     

THE ORIGIN OF TETRAPODS-PAST ANDPRESENT HYPOTHESES

HistoricalreviewoneshouldexpectthatanewtheorychangesorimprovestheunderstandingofPhylogeneticquestions.ThatdoesnotseemtobetrueoftheoriginoftetrapodsasRosenetal.(l98l)havealreadyshowninthecaseoftheapPearanceofDarwin's'ontheoriginofsPecies"inl859.Incontrast,thehistoryofthedevelopmentofhypothesesontheoriginoftetrapodsdemonstratesthatdiscoveryofnewextantorfos-silforms(Tab.l)shapesourunderstandingoftherelationshipoftetrapodstofishes.Thefrstextantlungfishwasdiscoveredinl836inSouthAmerica(Fitzinge…     

NEW TAXA OF ILEX FROM THE PEOPLE''''S REPUBLIC OF CHINA

llex strigillosa T.R.DUDLEY,sp.nov. 〔Section Pseudoaquifolium S.-Y.HU(1950)Series Lougecaudatae S.-Y.HU(1950)〕. DIAGNOSIS: A I.kengii S.-Y.HU(1950)affinis sed ramulis et gemmis terminalis,dense cinerascentibus puberulento-strigillosis,stipulis tenuiter membranaceis minutis0.1mm longis vel minus fugacibus cito caducis,petiolis denso cinerascentibuspuberulento-strigillosis aliquado subglabris laminis versus,laminis foliorum mino-ribus 4—7.5cm longis 1—2cm latis basibus acutis ad attenuatis apicibussensim acuminatis vel caudato-acuminatis acuminibus brevioribus 5—10(—15)mm longis marginibus integris vel subintegris conspicue sinuolatis et apicibus     

SPATIAL DISTRIBUTION OF ZOOPLANKTON IN THE MAIN STEM OF THE MIDDLE YANGTZE RIVER北大核心CSCD

To better understand zooplankton distribution and its relationship with the physical-chemical factors in middle Yangtze River, we collected 20 zooplankton samples from segments at Yichang, Jingzhou, Yueyang, Wuhan and Hukou in October, 2016. A total of 23 species that belong to 13 families and 14 genera were identified, among which 16 species belong to Rotifera, 4 to Copepoda and 3 to Cladocera. Among the five segments, the highest number of zooplankton species was detected at Hukou (9 species), while the lowest was at Yueyang (5 species). The average density at Wuhan (10.94±5.81) ind./L was higher than that at Hukou and the other segments. Rotifers (3.41±0.21) ind./L were dominant in the zooplanktonic community, and Keratella valga, Synchacta atylata and Keratella cochlearis were the dominant species. The average density of copepods (mainly nauplius) was (0.75±0.07) ind./L. Cladocera had the lowest average density. Similarly, the zooplankton biomass at Wuhan was also higher than that at Hukou and the other three segments. Comparing with studies at other segments of Yangtze River, we detected lower zooplankton diversity in our investigation. Spearman correlations indicated that the biomass and diversity of zooplankton were significantly and positively correlated (P<0.05) to chlorophyll a. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

THE GROWTH OF THE STEM TIP OF KALANCHOËU CV. ‘BRILLIANT STAR’

Stein , Diana B. and o . L. Stein . (Montana State U., Missoula.) The growth of the stem tip of Kalanchoë cv. ‘Brilliant Star.‘ Amer. Jour. Bot. 47 (2) : 132—140. Illus. I960.–The purposes of this investigation were (1) to define as clearly as possible the events in the shoot apex and its immediate derivatives during the ontogeny of the shoot; and (2) to determine the changes which occur during the transition from a vegetative to a reproductive meristem. Rate of leaf production in Kalanchoë is basically constant. The rate of leaf growth subsequent to the early primordial state is, however, dependent on the age of the plant and on the environment in which the plant is grown. By keeping these factors constant a correlation can be demonstrated between the size of the youngest visible leaf and the microscopic primordia. Throughout its ontogeny the general architecture of the shoot apex remains essentially the same. Two tunica layers cover the corpus in the vegetative shoot apex, and even in the flowering meristem these 2 layers can be detected. The apex is essentially flat and blends into the adjacent leaf primordia early in the plastochron. About 10 days after flower induction has been started the apex changes its form to a dome, primarily by increased cell division. At the same time the rate of elongation of the youngest internodes increases thus placing the flowering stem tip atop an elongated stem. Axillary development is ultimately responsible for the development of a dichasium.     

THE RELATIVE PHYSIOLOGICAL EFFECTS OF β-RAYS OF DIFFERENT VELOCITIES

1. The physiological effect upon the eggs of Nereis of homogeneous groups of β-rays of different velocities is proportional to their ability to ionize air. 2. β-rays of low velocity produce a greater amount of physiological change than the same number of rays of high velocity. 3. These conclusions are consistent with, but do not prove, the view that the physiological effects of radiations from radium and x-rays are due to the production by them of an ionization of some substance in the egg.     

THE POTENTIAL FOR PALAEOBOTANY IN THE EXPLANATION OF CHINA''''S PLANT GEOGRAPHY

The distributions of many plant taxa in China at the present day indicate centres of floristic importance which may be ancient,and have evolutionary significance,or which may be only their latest locations in a Cenozoic history of migrations.This paper summarizes the present and Cenozoic distributions in China of the following taxa:Nitraria,Ephedra,Carya,Liquidamber,Pterocarya,Betulaceae.It is concluded that the centres of importance of the named genera are different now from what they were at some time in the Cenozoic past;each has accomplished major migrations and suffered significant extinctions during that period.The history of the Betulaceae is less clear but in principle soluble.