THE EFFECT OF TEMPERATURE ON THE MECHANICAL ACTIVITY OF THE GILLS OF THE OYSTER (OSTREA VIRGINICA Gm.)

1. The method is described whereby the rate of flow produced by the gills of the oyster can be measured accurately. 2. The rate of doing work in maintaining a constant current along the glass tube can be expressed by the formula W = 2πlµ S ², where W = ergs/sec., l = length of the tube, µ = viscosity in poises, and S = speed at the axis of the tube. 3. The relationship between the rate of doing work and the temperature cannot be described by the equation of Arrhenius. 4. The optimum temperature for the mechanical activity of the gills lies between 25° and 30°C. Below 5° no current is produced, though the cilia are beating. Ciliary motion stops entirely at the freezing temperature of sea water. 5. The factors responsible for the production of current are discussed. The study of the relations between the variability of the rate of flow and the temperature shows that between 15° and 25°C. the absolute variability remains constant and increases considerably above 25° and below 15°. The rôle of the coordination in the production of current is discussed, and the conclusion is reached that coordination is affected by the changes in temperature.     

THE BIOLOGY OF THE RICE WEEVIL, CALANDRA ORYZAE (L.)

The length of the developmental instars of Calandra oryzae has been estimated at relative humidities of 50, 60, 70 and 80% at 21° C., at 70% at 18, 25 and 30° C., and at 80% at 18° C., by the dissection daily of samples of infested wheat-grains. The results are expressed as a median obtained by the method of probit analysis. Comparison of this method, with estimates of median and mean obtained by orthodox arithmetical methods from similar work on Rhizopertha , show that the probit method gives good estimates.
About 90% of the eggs laid are fertile. Normally only one adult will develop in a grain, all other individuals being destroyed by cannibalism. The sex ratio is unity. It was not possible to cross C. oryzae and C. granaria.
The daily oviposition rate of C. oryzae at 17, 21 and 25° C. increases with relative humidity. There is a critical point at about 60% r.h . below which egg laying declines rapidly, and mortality is high. At 100% r.h . the oviposition rates per female per day are approximately 1.3, 2.5 and 3.4 at 17, 21 and 25° C. respectively.
In experimental conditions most eggs per grain are obtained by giving isolated females one grain each, but more eggs are laid by females given more than one grain. Daily egg output is reduced by grouping females or including males. In culture, depths of grain up to 7 cm. do not discourage egg laying.     

THE EFFECT OF TEMPERATURE ON REPRODUCTION BY THE ALATAE OF PEMPHIGUS BURSARIUS (L.)

The reproductive rate of the winged forms of Pemphigus bursarius was studied at temperatures between 38 and 82° F. The fundatrigeniae gave the greatest total reproduction at about 60° F. but the highest reproductive rate at 70–81° F. Corresponding temperatures for the sexuparae were 55 and 67° F. approximately. The average outdoor air temperatures prevailing at the time when the respective winged forms are most abundant correspond closely to the temperatures required by the alatae for maximum reproduction. On a basis of temperature, adult sexuparae trapped underground can expect to survive about 12 days in early September and about 30 days at the end of October.     

THE ADDUCTOR AND RETRACTOR MUSCLES OF THE VELIGER OF PECTEN MAXIMUS (L.) (BIVALVIA)

In Pecten maximus (L.), retractor and adductor muscles becomefunctional in the early veliger larva. The twelve-day-old veligerhas four pairs of velar retractors, three pairs of retractorsattached to the posterior body wall and an anterior adductor.The pediveliger has in addition, pedal retractor muscles anda posterior adductor. The retractors consist of striated muscle:the adductors have both smooth and striated portions. The retractorsattach near the hinge, branch to a greater or lesser extent,then attach to specific areas of the velum, posterior body walland foot. Some features of the branching and of the dispositionof points of attachment form a pattern which exhibits mirrorsymmetry about the plane between the two shell valves. Thispattern is characteristic of the species. It is deduced thatretraction and protraction of the velum result from co-ordinatedsequences of muscle contractions. ^*Present address: Forest Products Research Centre, P.O. Box1358, Boroko, Papua New Guinea. (Received 15 June 1984;     

橐吾属的分类系统

橐吾属是菊科(Compositae)中的一个大属,全世界约有130种,主产亚洲温带地区,仅少数几个种分布至欧洲。我国有111种,大部分种类产西南地区。本属依据形态特征分为6个组。     

香薷中的化学成分

从香[Eltholtzia ciliata(Thund.)Hyland]中分出14个化合物,用波谱和化学等方法确定为6-甲基三十三烷(Ⅰ),13-环己基二十六烷(Ⅱ),β-谷甾醇(Ⅲ),棕榈酸(Ⅳ_a),亚油酸(Ⅳ_b),亚麻酸(Ⅳ_c),熊果酸(Ⅴ),5-羟基-6、7-二甲氧基黄酮(Ⅵ),5-羟基-7、8-二甲氧基黄酮(Ⅶ),5、7-二羟基-4′-甲氧基黄酮(Ⅷ),5-羟基-7、4′-二甲氧基双氢黄酮醇(Ⅸ),β-谷甾醇-3-β-D-葡萄糖甙(Ⅹ),5-羟基-6-甲基-7-O-α-D-半乳吡喃糖双氢黄酮甙(Ⅺ),刺槐素-7-O-β-D-葡萄糖甙(Ⅻ)。其中化合物Ⅺ为新化合物,除(Ⅳ_b)和(Ⅳ_c)外,其余为首次从该属植物中得到。