Description: Description of 64 species of fresh‐water Fishes of the suborder Characoidei (Cypriniformes), collected by Dr. K. H. Lüling during his 1959/60 Expedition in lower Ucayali and Iquitos regions. New forms for science (about 10 per cent of the collected species) are: a new genus, Oxybrycon, which seems to be close to Leptobrycon and Macropsobrycon; a Hemigrammus‐species and 2 Hyphessobrycon‐species; a Cheirodon (the genus was not signaled from Peruvian Amazon); and a Serrasalmus. Besides, 10 species seem to be new for the concerned territory, whereas 2 other forms have been described in former papers (see References). Some identification‐Keys are given, concerning Amazonian Triportheus and Schizodon, as well as concerning one Curimatus‐group of species. Finally a list of the characoid Fishes, known to occur in the Iquitos surroundings and in the lower Ucayali, is given.

Description: Simple solutions are found for barotropic planetary oscillations of a fluid in a $\beta$-plane, both in the unbounded plane and in enclosed basins of various shapes. These are compared with analogous motions of fluid on the surface of a sphere. The motions in a $\beta$-plane are considered in part I. It is shown that waves can exist which may be oriented in any horizontal direction; they drift westwards with a velocity $\beta$/$\kappa^2$, where $\kappa$ = 2$\pi$/wavelength is the absolute wave number. The group velocity of these waves makes an angle 2$\alpha$ with the eastward direction, where $\alpha$ is the angle made by the vector wave number. The reflexion of such waves from a fixed boundary is studied; both the wavelength and orientation of the reflected wave differs from that of the incident wave in general. Westward-drifting motions are typical of motions on an unbounded $\beta$-plane. On the other hand, motions in an enclosed basin can be described as a carrier wave modulated by a real amplitude function f(x, y). The equation for f is equivalent to the equation for a vibrating membrane clamped at the boundaries; normal mode solutions can be obtained explicitly for a variety of shapes of basin, including the rectangle, circle and equilateral triangle. Motions on a sphere are considered in part II. On an unbounded sphere the general solutions are spherical harmonics S$_n$($\theta$', $\phi$') where ($\theta$', $\phi$') denote spherical co-ordinates with respect to some pole P', not necessarily on the axis of rotation. The motions are propagated by a westward drift of the pole P' round a circle of latitude, with angular velocity 2$\Omega$/n(n+1). Solutions in enclosed basins have been found not only when the boundaries of the basin are circles of latitude, but also when the boundaries are meridians of longitude. The validity of the $\beta$-plane approximation is investigated, first by determining the asymptotic forms of the surface harmonics when the wave number n is high; secondly by comparing the periods of the lower modes in an enclosed basin on a sphere with the corresponding periods for the $\beta$-plane. At high wave numbers the solutions in terms of spherical harmonics do generally reduce to motions satisfying the $\beta$-plane equations: but exceptions occur in the neighbourhood of certain caustic lines, where the variation of $\beta$ must be taken into account. Thus it is possible for a wave motion to be trapped in the neighbourhood of a great-circle, the amplitude falling off rapidly to either side. The plane of this great-circle rotates slowly round the axis of rotation of the sphere. On the other hand, in an enclosed basin centred on the equator some of the lower modes of oscillation agree very well with those derived from the $\beta$-plane approximation. Even when the radius of the basin is as great as one quadrant, the periods of the four lowest symmetric modes agree within 10%.

Description: Two new species of histioteuthid squids from the North Atlantic, Calliteuthis elongata and C. corona are described and Calliteuthis reversa Verrill is redescribed from the type and supplementary material. C. verrilli Pfeffer is placed in the synonymy of C. reversa. The status of all of the names of Atlantic species of Calliteuthis is discussed. Detailed illustrations are given of C. reversa, elongata and corona.

Description: The biology of Tripneustes has been studied for several years in Miami and Bermuda. It spawns in the spring and summer but with a very different spawning pattern in different years. First spawning seems to be triggered by temperature, and successive spawnings by attainment of a gonad size which increases during the season. Winter growth of the gonad and its rate of build up between spawnings is negatively correlated with temperature, as is test growth. Hermaphroditism was common in a year group which was in the immature stage during an unusually cold winter. A tentative estimate has been made of food intake and of the efficiency of its conversion into urchin tissue.