"NONSENSE" ORIENTATION AS A POPULATION VARIANT

Using 2,570 Mallard, the "nonsense" orientations of two largely separate stocks are compared. Slimbridge birds head off predominately northwestwards throughout the season. Birds caught at Peakirk showed a similar orientation during the early autumn, but during the winter scattered virtually at random, yet without behaving as if disorientated.
A sample of 188 Mallard from London orientated in southerly directions both in autumn and spring, yet could not be responsible for the change at Peakirk because they would not disperse so far. 180 young Mallard from Slimbridge and London stocks were reared in large aviaries. Their first flights were too abbreviated for conclusive results but differences between the stocks were indicated and it is possible that "nonsense" orientations are not learned responses to the local topography.
Ringing recoveries show that the timing of the arrival of immigrants from the Continent coincides with changes in orientation at Peakirk and that their distribution is such that it could explain the different results at Slimbridge. Preliminary releases of Swedish-caught Mallard strongly support the argument.
The implications for the study of bird navigation are briefly discussed.     

作物对缺水环境的感知及其反应

植物面对多变的缺水环境,如何来感知环境然后做出自身形态、生理生化等一系列反应。本文评述了缺水信号的感知、反应以及抗旱的方式及其抗旱的遗传学基础。     

THE SENSE ORGANS OF BIRDS

The eyes and ears of birds are compared with those of man so far as the existing state of knowledge allows, and an attempt is made to correlate resemblances and differences with the evolutionary history and the functional requirements of the present day. It is shown that the characteristic shape of the central fovea of the bird's retina cannot be accounted for by supposing that it increases acuity; it is more likely a device for emphasizing angular movements. A brief account of Menner's theory of the pecten is given.
In default of any satisfactory physiological data, an attempt is made to assess the indirect evidence relating to the frequency range and discriminative power of a bird's ear. The conditions for the unambiguous determination of the direction of a sound source are discussed and it is suggested that the asymmetry of the ears of owls is correlated with an enhanced directional sensitivity which, in turn, is related to the dependence of owls on hearing rather than sight in their hunting.
Reference is made to the senses of smell and touch in birds. And there is a brief discussion of the problems of "time" and "direction" senses.     

THE CRUCIFORM MUSCLE AND ITS ASSOCIATED SENSE ORGAN IN SCROBICULARIA PLANA (DA COSTA)

Long dendritic processes from neurones of the sense organ ganglionpenetrate the epithelial lining of the narrow and short ductsituated between the intramuscular slit and a large posteriorcavity which opens to the siphonal space through a narrow canalin the sense organ papilla. Motor nerve fibres innervate theanterior ends of the cruciform muscle strands. The latter becomesstretched during opening of animal and contracted during closure.The slit is widened during opening and narrowed during closure.The sense organ responds to foul water suggesting that it isa chemoreceptor for this stimulus. (Received 10 July 1977;     

中国角蟾亚科精子形态比较及分类学讨论(两栖纲：锄足蟾科)

应用光镜和电镜对角蟾亚科短腿蟾属,拟角蟾属和角蟾属3属18种精子的形态结构进行观察和比较。并通过计算机对其各部位长度进行了测量和计算,结果表明角蟾亚科精子的共同特征是：精子主要由头和尾两部分组成,头部呈螺旋状,尾部为波状或弯曲状,但精子的量度和头部形状在属间和种间存在明显差别,角蟾亚科的精子可分为3类,该亚科精子形态的差异与成体形态学研究结果基本相吻合,精子形态的差异可为该亚科属,种的划分,亲缘关系研究提供新依据。     

中国大鲵侧线器官的研究

本文以光镜和扫描是镜手段研究了中国大鲵幼体，亚成体及成体头部及躯干部表皮中的侧线器官，即电接受壶腹器官，机械接受的表面神经丘和陷器官的分布，形态和发展变化。壶腹器管仅存于幼体头部，变态结束后消失，后两种终生存在，但前者按一定路线和方向排列，后者仅存于头部，陷在表皮中，文章探讨了壶腹器官的原始性，其消失与生活习性以及由水登陆进化的关系；对三种器官的形态及其它有尾类的侧线器官进行了比较。