The elongation of the embryo is accompanied by an elongation of the blastopore, which soon becomes dumb-bell shaped (fig.
Ebenezer Kinnersley (1711-1778) of Philadelphia made useful observations on the elongation and fusion of iron wires by electrical discharges (Phil.
Bidwell's results for iron and nickel were confirmed, and it was further shown that the elongation of nickel-steel was very greatly diminished by tension; when 2 Joule believed that the volume was unchanged.
The Angora rabbit is characterized by the extreme elongation and fineness of the fur, which in good specimens reaches 6 or 7 in.
Knott on magnetic twist, which will be referred to later, led him to form the conclusion that in an iron wire carrying an electric current the magnetic elongation would be increased.
At the same time some Acari, like Eriophyes (Phytoptus) and Demodex, have the body elongated and annulated, but in these groups the elongation of the body is caudal or post-anal, as is attested by the position of the anus far forwards on its ventral surface.
This may consist simply in attaching one end of the wire to an index lever and the other to a fixed support, or the elongation of the wire may cause a rotation in a mirror from which a ray of light is reflected, and the movement of this ray over a scale will then provide the necessary means of indication.
Till recently the galagos have been included in the family Lemuridae; but this is restricted to the lemurs of Madagascar, and they are now classed with the lorises and pottos in the family Nycticebidae, of which they form the section Galaginae, characterized by the great elongation of the upper portion of the feet (tarsus) and the power of folding the large ears.
This order can be traced with certainty back to the early Jurassic epoch, while the Permian fossil Eugereon, and the living order - specially modified in many respects - of the Thysanoptera indicate steps by which the aberrant suctorial and piercing mouth of the Hemiptera may have been developed from the biting mouth of primitive Isopteroids, by the elongation of some parts and the suppression of others.
The forward portion of the anterior coelom shared in the constriction and elongation of the preoral lobe; but its hinder portion was dragged up along with the water-pore and formed a canal lying moccth ive along the outer wall (the gerei tatpore parietal canal).