LAP 



[248 ] 



LAV 



marine blue, used by painters, a 

 pigment remarkable for the dura- 

 bility of its colour. 



LA'PIS CETI'TES. Eagle- stone. A min- 

 eral which derives its name from 

 the ancient belief that it was found 

 in the nests of the eagle. It is a 

 variety of iron ore, commonly met 

 with in the argillaceous mines of 

 this country. Its supposed virtues 

 are described by Dioscorides, (Etius, 

 and Pliny, who assert that if tied 

 to the arm it will prevent abortion ; 

 if fixed to the thigh it will facili- 

 tate delivery. 



LA'BYNX. (\dpvyg, Gr.) The upper 

 part of the wind-pipe or trachea ; 

 that cartilaginous projection in the 

 throat known as the pomum 

 Adami, which strictly is formed 

 by one of the cartilages of the 

 larynx only, namely, the thyroid. 

 The larynx consists of five cartila- 

 ges, the cricoid, thyroid, two ary- 

 tsenoid, and the epiglottis. 



LA'TERITE. The name given to a 

 ferruginous clay, mottled red and 

 yellow. When first dug from its 

 bed, it is soft and easily fashioned 

 into the form of bricks or large 

 square masses for building; it 

 rapidly indurates on exposure to 

 the atmosphere, and, as far as is 

 yet known, is destitute of fossils. 



LATIRO'STEOUS. (from latus, broad, 

 and rostrum , a beak, Lat.) Broad 

 beaked. 



LA'TITUDE. (latitude, Lat. latitude, Fr~ 

 latitudine, It.) The latitude of a 

 place on the earth's surface is its 

 angular distance from the equator, 

 measured on its own terrestrial 

 meridian : it is reckoned in degrees, 

 minutes, and seconds, from up to 

 90, and northwards or southwards 

 according to the hemisphere the 

 plane lies in. Thus the observa- 

 tory at Greenwich is situated in 

 51 28' 40" north latitude. Lati- 

 tude may also be thus defined, the 

 angular distance between the di- 

 rection of a plumb-line at any 



place and the plane of the equator. 



LA'TROBITE. A mineral, thus named 

 after Latrobe, having been found 

 by him on the coast of Labrador. 

 Colour, pale pink ; specific gravity 

 2 -8. Occurs massive and crys- 

 tallized. 



LA'TTICED. In conchology, shells 

 having longitudinal lines or furrows 

 decussated by transverse ones, re- 

 sembling lattice-work. 



LA'RVA. (larva, a mask, Lat.) An 

 insect in its caterpillar state, before 

 it has attained its winged or 

 perfect state. Some insects, as the 

 butterfly, moth of the silkworm, 

 &c., pass through four distinct 

 states, namely, the egg ; the larva, 

 or caterpillar ; the pup% or chry- 

 salis; and the imago, or perfect 

 insect. The egg, which is de- 

 posited by the perfect insect, gives 

 birth to a caterpillar, or larva ; 

 an animal, which, in outward 

 shape, bears not the slightest re- 

 semblance to its parent, or to the 

 form it is itself afterwards to 

 assume. It has, in fact, both the 

 external resemblance, and the 

 mechanical structure, of a worm. 

 The same elongated cylindric 

 shape, the same annular structure 

 of the denser parts of the integu- 

 ment, the same arrangements of 

 longitudinal and oblique muscles 

 connecting these rings, the same 

 apparatus of short feet, with claws, 

 or bristles, or tufts of hair, for 

 facilitating progression ; in short, 

 all the circumstances most charac- 

 teristic of the vermiform type are 

 equally exemplified in the different 

 tribes of caterpillars, as in the 

 annelida. These external invest- 

 ments, which hide the real form of 

 the future animal, have been 

 compared to a mask; so that the 

 insect, while wearing this disguise, 

 has been termed larva, the Latin 

 name for a mask. Roget. 



LA'VA. (This word, according to 

 Kirwan, is derived from the Gothic, 



