E P 



[254] 



L E P 



of enormous size, fragments of 

 stems occurring upwards of forty 

 feet in length. Their internal 

 structure has been ascertained to be 

 intermediate between coniferse and 

 Iycopodiacea3. In some points of their 

 structure they resemble coniferse, 

 but in other respects, setting aside 

 their great magnitude, they may be 

 compared to lycopodiaceas. To bot- 

 anists, this discovery is of very 

 high interest, as it proves that those 

 system atists are right, who contend 

 for the possibility of certain chasms 

 now existing between the grada- 

 tions of organization, being caused 

 by the extinction of genera, or even 

 of whole orders, the existence of 

 which was necessary to complete 

 the harmony which it is believed 

 originally existed in the structure 

 of all parts of the vegetable king- 

 dom. By means of Lepidodendron, 

 a better passage is established from 

 flowering to flowerless plants, than 

 by either equisetum or cycas, or any 

 other known genus. Lindley and 

 Button. 



LE'PIDOIDS. A family of extinct fossil 

 fishes, found in the oolitic series ; 

 they were remarkable for their 

 large rhomboidal bony scales, which 

 were of great thickness, and cov- 

 ered with enamel. The scales of 

 lepidoids had a remarkable struc- 

 ture in being furnished on their 

 upper margin with a hook-like pro- 

 cess, placed like the hook or peg 

 near the upper margin of a roofing 

 tile ; this hook fitted into a depres- 

 sion on the lower margin of the 

 scale placed immediately above it. 



LEPI'DOLITE. (from XeTrte, a scale, 

 and X/0os, a stone, Gr.) The Lep- 

 idolith of "Werner ; Hemiprismat- 

 ischer Talk-glimmer of Mobs. A 

 mineral of a peach-blossom, red, 

 and sometimes grey colour, occur- 

 ring massive and in small concre- 

 tions. This mineral, at first view, 

 appears to be composed of small 

 grains, sometimes extremely mi- 



nute ; but these grains, among 

 which little pearly scales are often 

 interspersed, are themselves com- 

 posed of a great number of minute 

 folise or spangles, like those of mica, 

 from which circumstance it has 

 obtained its name. Its constitu- 

 ents have been variously stated. 

 According to some authors, it con- 

 tains silica 50-36, alumina 28-32, 

 potash 9-0, oxide of manganese 

 1'25, fluoric acid and water 5 '40, 

 lithia 5'50. It exhibits two axes 

 of double refraction, from which 

 circumstance it has been called 

 Di-axial mica. Prom the beauty 

 of its colour it has been cut into 

 snuff-boxes. 



LEPLDO'PTERA. (from XeTm-, a scale, 

 and Tnepov, a wing, Gr.) Scaly- 

 winged insects. Lepidoptera form 

 the tenth order of insects in Cuvier's 

 arrangement; they have four wings, 

 both sides of which are covered 

 with small coloured scales, resem- 

 bling farinaceous dust. This order 

 comprises butterflies, moths, and 

 sphinxes. The scales are attached 

 so slightly to the membrane of the 

 wing as to come off when touched 

 with the fingers, to which they 

 adhere like fine dust. When ex- 

 amined with the microscope, their 

 construction and arrangement ap- 

 pear to be exceedingly beautiful, 

 being marked with parallel and 

 equidistant stria?, often crossed by 

 still finer lines. The former of 

 these scales are exceedingly diver- 

 sified, not only in different species, 

 but also in different parts of the 

 same insect The proboscis of the 

 Lepidoptera is a double tube. In 

 the classification of the most mod- 

 ern naturalists, Lepidoptera consti- 

 tutes the fifth order of the class 

 Insecta ; sub-kingdom Annulosa. 

 LEPIDO'PTEEAL. } Belonging to the 

 LEPIDO'PTEKOUS. ) order Lepidoptera ; 



having wings covered with scales. 

 LEPIPO'STETJS. | (The Lepisosteus of 

 LEPISO'STETJS. j Lacepede. A genus 



