THERMAL RECEPTION IN FISHES

The reactions of catfish, sunfish, perch, and mummichog to temperature changes, as described in this paper, indicate that certain receptors supplied by the lateral-line nerve are concerned with thermal reception.     

ON CENTRAL MECHANISMS OF TASTE IN FISHES

The comparison of medullar units and facial nerve fibres activityin response to stimulation of skin chemoreceptors around themouth with solutions of hydrochloric and citric acid and sodiumchloride was carried out by means of extracellular recordingin immobilized carps. The afferent information concerning thechemical stimulus was found to be modified during synaptic processingin the primary brain centre. By means of an across neuron patternmodel some aspects of neural coding of chemical stimulus qualityand intensity in fishes were elucidated. It was disclosed inparticular that the qualitative peculiarities of the stimulus,but not the level of pH play the main role in coding of acidicstimuli (for the range of low concentration solutions).     

云南路南县黑龙潭水库及灌区的鱼类

云南路南县黑龙潭水库灌区的鱼类共有４８种;扣除外来种１２种,实有土著鱼种３６种,隶属于４目７科２８属。本文描记了新种大斑云南鳅ＹｕｎｎａｎｉｌｕｓｍａｃｒｏｓｉｔａｎｕｓＬｉ,ｓｐ．ｎｏｖ和叉尾云南鳅ＹｕｎｎａｎｉｌｕｓｆｏｒｋｉｃａｕｄａｌｉｓＬｉ．ｓｐ．ｎｏｖ,并对黑龙潭水库灌区的鱼类区系和动物地理学特征作了简要分析。     

CRITICAL ILLUMINATION AND FLICKER FREQUENCY IN RELATED FISHES

Flicker response curves have been obtained at 21.5°C. for three genera of fresh water teleosts: Enneacanthus (sunfish), Xiphophorus (swordtail), Platypoecilius (Platy), by the determination of mean critical intensities for response at fixed flicker frequencies, and for a certain homogeneous group of backcross hybrids of swordtail x Platy (Black Helleri). The curves exhibit marked differences in form and proportions. The same type of analysis is applicable to each, however. A low intensity rod-governed section has added to it a more extensive cone portion. Each part is accurately described by the equation F = F_max./(1 + e ^{-p log-p logI/I_i}), where F = flicker frequency, I = associated mean critical intensity, and I_i is the intensity at the inflection point of the sigmoid curve relating F to log I. There is no correlation between quantitative features of the rod and cone portions. Threshold intensities, p, I_i, and F_max. are separately and independently determined. The hybrid Black Helleri show quantitative agreement with the Xiphophorus parental stock in the values of p for rods and cones, and in the cone F_max.; the rod F_max. is very similar to that for the Platy stock; the general level of effective intensities is rather like that of the Platy form. This provides, among other things, a new kind of support for the duplicity doctrine. Various races of Platypoecilius maculatus, and P. variatus, give closely agreeing values of I_m at different flicker frequencies; and two species of sunfish also agree. The effect of cross-breeding is thus not a superficial thing. It indicates the possibility of further genetic investigation. The variability of the critical intensity for response to flicker follows the rules previously found to hold for other forms. The variation is the expression of a property of the tested organism. It is shown that, on the assumption of a frequency distribution of receptor element thresholds as a function of log I, with fluctuation in the excitabilities of the marginally excited elements, it is to be expected that the dispersion of critical flicker frequencies in repeated measurements will pass through a maximum as log I is increased, whereas the dispersion of critical intensities will be proportional to I_m; and that the proportionality factor in the case of different organisms bears no relation to the form or position of the respective curves relating mean critical intensity to flicker frequency. These deductions agree with the experimental findings.     

喹乙醇在鱼体内蓄积及其对鱼类的影响

本文以含 35 0mg/kg和 4 0 0mg/kg喹乙醇的饲料经 99d分别连续投喂鲤和银鲫 ,以测定喹乙醇在鲤和银鲫体内的蓄积及其对鲤、银鲫的影响。试验结果表明 ,无论是银鲫单养还是鲤鲫混养 ,无论是鲤还是银鲫 ,试验组喹乙醇在肝脏组织中蓄积量最高 ,99d单养银鲫组可达 10 0 5 7± 0 0 15 (3)mg/kg ,鲤鲫混养组银鲫、鲤分别达 10 10 7± 0 2 2 6 (3)mg/kg,9 883± 0 0 32 (3)mg/kg ,肾脏次之 ,99d单养鲫鱼组的银鲫 ,鲤鲫混养组的银鲫、鲤分别为 7 4 94± 0 0 6 4 (3)mg/kg,7 777± 0 138(3)mg/kg和 7 6 0 8± 0 0 86 (3)mg/kg ,肌肉中较低 ,分别为 0 1170± 0 0 0 3(3)mg/kg ,0 16 0± 0 0 0 3(3)mg/kg,0 4 86± 0 0 0 6 (3)mg/kg;经检验三种组织器官中的蓄积量差异显著 (P <0 0 5 )。由于喹乙醇在鱼体内的蓄积 ,虽鲤鲫混养组的银鲫、鲤的相对增重率达到 10 2 7%和 110 7% ,但是它们的抗应激反应率明显下降 ,而且随喹乙醇摄入量的增加下降趋势更为明显 ,当给予一定程度的应激刺激后 ,单养鲫鱼组的银鲫应激反应率由 5 8d的4 4 8%上升到 99d的 6 4 3% ,鲤鲫混养组的银鲫和鲤分别由 5 8d的 6 6 7%和 4 6 2 %分别上升到 99d的 88 3%和76 9% ,无论是 5 8d还是 99d ,试验组与对照组间差异显著 (P     

我国泥盆纪鱼类的分布、组合和性质

文中记述了我国泥盆纪鱼类化石分布情况,并根据已描述的化石建立8个组合。     

原位杂交和原位PCR技术在鱼类基因定位中的应用

染色体原位杂交（ ｉｎ ｓｉｔｕ ｈｙｂｒｉｄｉｚａｔｉｏｎ, ＩＳＨ）是基因物理定位的主要方法之一,它根据核酸分子碱基互补配对的原理,将标记的外源核酸探针与染色体上变性处理后的单链ＤＮＡ互补配对,再经检测而将靶顺序在染色体上的位置显示出来。 原位ＰＣＲ技术是将原位杂交与ＰＣＲ技术有机的结合,在原位扩增目的ＤＮＡ片段,并在原位检测其扩增产物,因而兼有ＰＣＲ及原位杂交技术二者的优越性：既可以同时获得组织及细胞的形态结构信息与分子信息,进行定性、定位分析,又具有比原位杂交更好的敏感性与专一性。 染色体原位…     

东亚似鮈类鱼类的起源和演化

本文采用分支扩散法和分支离散法两种生物地理学方法分析了似　类的起源和演化。结果说明似类于第三纪末起源于中国北方的原始类,逐步向南扩散。在其物种分化过程中可能存在南北两个分化中心。