STRUCTURE OF THE EGG‐SHELL OF CULEX PIPIENS AND MANSONIA AFRICANA (CULICIDAE, DIPTERA)Lincoln, D. C. R.
doi: 10.1111/j.1469-7998.1965.tb01997.xpmid: N/A
Eggs of Culex pipiensL. are laid in rafts on the surface of still or slow moving water, whereas those of Mansonia africana (Theobold) are deposited beneath tho surface of the water on the undersides of floating leaves (Laurence & Smith 1958; Laurence 1959). The eggs of both species are surrounded by air, those of Culex pipiens are in direct contact with the external atmosphere, whereas those of Mansonia africana are partially surrounded by a bubble of air trapped between them. The anterior onds of the eggs of Mansonia africana project through the bubble of air into the surrounding water. This bubble of air is only found around living eggs and disappears if tho eggs die and shortly before they hatch. Iyengar (1935) has shown that the eggs of Ficalba minima Theo. although often deposited on the same leaf as those of Mansonioides, are laid above the water line and resemble in structure those of Culex and Coquillettidia. The structure of the egg‐shell of both Culez pipiens and Mansonia africana is described and discussed.
ECOLOGY AND BEAVIOUR OF THE VERVET MONKEY, CERCOPITHECUS AETHIOPS, LOLUI ISLAND, LAKE VICTORIAHall, K. R. L.; Gartlan, J. S.
doi: 10.1111/j.1469-7998.1965.tb01999.xpmid: N/A
A 1‐month survey of the vervet monkeys of Lolui, an uninhabited island of 11 square miles in Lake Victoria, indicated a population size of about 1,500. Reliable counts of 46 groups were made, giving a mean of 12. Age and sex analyses of 18 groups showed a ratio of 1: 1.4 adult males to adult females, 1: 1 for adults and immatures combined.
AN ANATOMICAL STUDY OF THE ABDOMINAL NERVOUS AND MUSCULAR SYSTEMS OF DRAGONFLY (AESHNIDAE) NYMPHSMill, P. J.
doi: 10.1111/j.1469-7998.1965.tb02000.xpmid: N/A
The musculature of the fourth to eighth abdominal segments is typically composed of twenty pairs of segmental muscles associated with the body wall. In the first to third and ninth and tenth segments certain modifications to the basic plan occur in association with the abdominal‐thoracic junction, the respiratory apparatus and the anal appendages. In some segments there are also paired muscles associated with the alimentary canal. Two large transverse muscles are present in the abdomen. There are eight abdominal ganglia, the first seven of which each give rise to three pairs of lateral nerves, the eighth to five pairs. In addition there are ten median abdominal nerves. The innervation fields of the various nerves are described. The first three pairs of lateral nerves of the last ganglion are homologous with the lateral nerves of the other abdominal ganglia; the fourth pair innervates most of segment nine; and the fifth pair innervates the remainder of segment nine, segment ten and the anal appendages. Certain of the abdominal muscles are innervated by branches from two different nerve roots. In segments six and seven the anterior point of attachment of the longitudinal stretch receptors is normally different from that in the other abdominal segments. This is discussed in the light of the types of movement which involve the abdomen and it seems apparent that these receptors are affected not only by swimming and abdominal flexion, as are the other longitudinal stretch receptors, but also by respiratory movements. Two distinct types of epidermal sensilla are present on the abdomen, spines and hairs. The former are the more numerous on the body, the latter on the anal appendages.
REPAIR OF THE SHELL IN SPECIES OF ANODONTABEEDHAM, G.E.
doi: 10.1111/j.1469-7998.1965.tb02003.xpmid: N/A
The process of shell repair in specios of Anodonta is re‐examined in the light of current views on the mantle/shell relationship in the Lamellibranchia. Experiments indicate that the epithelia of the general outer mantle surface and mantle isthmus normally responsible for the production, respectively, of the inner layer of the valves and of the ligament can regenerate material comparable with that produced by the outer fold of the mantle edge. The process, which is usually preceded by a phase in which amoebocytes are involved, consists initially of the formation of appreciable quantities of organic material (conchiolin). Much of this conchiolin is histochemically comparable with that of the periostracum and the outer layers of the valves and ligament secreted during marginal increment of the shell by the inner and outer surfaces, respectively, of the outer mantle fold. This type of conchiolin is probably rich in quinone‐tanned protein (sclerotin). Repair of the valves is completed by the calcification of this organic matrix to form an outer calcareous (prismatic) layer, followed by the desposition of inner (nacreous) layer material.