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In cartography, projections are ways of representing the earth's surface on a map. Because the earth is round, any map distorts the area it represents (just as flattening out an orange peel distorts its original shape). Only a globe can be really accurate. Different types of projection have been worked out, each suited to a particular purpose. The two main ones are Conical and Cylindrical. The former shows each hemisphere as a cone which has been unrolled. A Cylindrical Projection shows the earth as though it were an unrolled cylinder. Mercator's projection is cylindrical. Its main fault is that it makes the Equator out to be the same length as all other latitudes, even those near the Poles, which are really only a few miles long. Thus countries near the Poles appear far larger than they really are.
 Research Projections
Stilts are poles with stirrup-like projections for the feet placed at some distance from the bottom and used for walking over rough ground. They were used for crossing rivers, scaling castle walls and as a diversion.
Research Stilts
The amoeba (sub Phylum Sarcodina) is a simple single celled animal of the group sarcomastigophora. They move by extending lobe-like projections of their cytoplasm called pseudopodia. Food is obtained by phagocytosis.
Research Amoeba
Crab is a popular name for crustacea of the sub-order Brachyura and to many of the Anomura of the order Decapoda. The true crabs (Brachyura) are characterised by having a small abdomen and the head and breast are united, forming the cephalothorax, and the whole is covered with a strong carapace.
The mouth has several pairs of strong jaws, in addition to which the stomach has its internal surface studded with hard projections for the purpose of grinding the food. The stomach is popularly called the 'sand-bag'; a little behind it is the heart, which propels a colourless lymph (the blood) to the gills (' dead man's fingers'). The liver is the soft, rich yellow substance, usually called the fat of the crab. They 'moult' or throw off their calcareous covering periodically.
They have ten legs, of which the first pair are modified as claws, and the remaining pairs are used for locomotion. There are many genera, distinguished from the lobster and other macrurous or long-tailed decapods by the shortness of their tail, which is folded under the body. Their eyes are compound, with hexagonal facets, and are pedunculated, elongated, and movable. Like most individuals of the class, they easily lose their claws, which are as readily renewed. They are generally scavengers, living on decaying animal matter, though others live on vegetable substances, as the racer-crabs of the West Indies, which suck the juice of the sugar-cane.
Most crabs inhabit the sea, others fresh water, some the land, only going to the sea to spawn. Of the crabs several species are highly esteemed as an article of food, and the fishery constitutes an important trade on many coasts. The large edible crab (Cancer pagurus) is common on the British shores, and is much sought after.
Research Crab
In botany and zoology, the term dentate refers to something having a toothed margin or tooth-like projections.
Research Dentate
The gaboon viper (Bitis gabonica) is a large venomous viper that occurs in African rainforests. It has brown and purple markings and hornlike projections on its snout.
Research Gaboon Viper
Pseudopodia are temporary projections from the cell of a Protozoan, leucocyte, etc., used for feeding and locomotion.
Research Pseudopodia
The ethmoid bone is a bone of very spongy substance, somewhat irregularly cubical in shape, lying at the root of the nose, between the two orbits or eye-sockets, and forming part of the bony wall of both. The segment of the ethmoid bone which forms part of the inner wall of the orbital cavity is called the orbital plate, while another segment, forming the roof and back part of the septum of the nasal cavity is called the perpendicular plate. Two irregularly shaped, shell-like projections from the ethmoid bone are called the superior and middle turbinate (conchae), and form ledges on the inside wall of the nasal cavity.
Research Ethmoid Bone
In anatomy, the Haemal Cavity is a term applied to the cavity which contains the great centres of circulation in the Vertebrata, together with the digestive and respiratory apparatus. The Haemal Arch is the arch formed by the projections anteriorly of the ribs and the sternum from the vertebrae.
Research Haemal Cavity
The metacarpus are the five long bones which extend between the carpals of the wrist and the phalanges. The metacarpals are numbered beginning with that of the thumb. The head of each metacarpal bone is bulbous at the site of articulation with the phalanges, and features small projections or knobs to which the ligaments of the fingers and palm attach.
Research Metacarpus
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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