LENTICELS. 



[ 458 ] 



LEPISMA. 



parent, being less disagreeable and less vo- 

 latile than oil of turpentine. Glycerine may 

 often be substituted. 



LENTICELS. Structures found upon 

 the surface of young stems, especially of 

 most of the Dicotyledonous shrubs and 

 trees. They first appear on the yearling 

 shoot as little specks, of a different colour 

 from the rest of the epidermis. Towards 

 the winter, or in early spring, the epidermis 

 splits transversely over the lenticels, which 

 become then slightly projecting papillae, 

 frequently divided into lips, as it were, by a 

 median furrow. The surface of the papilla 

 is now brown ; and it is of corky character 

 for some little distance inwards. As the 

 branch grows, the lenticels become drawn 

 out laterally, so as to appear like cross 

 striae. They are subsequently lost sight of 

 by the bark splitting through them, as in 

 the apple or beech, or by the bark peeling 

 off (plane). 



Microscopic examination of sections shows 

 that they are mere hypertrophal produc- 

 tions from the epiphlceum, or suberous layer 

 of the BARK, and have no connexion with 

 the liber or cambium. DeCandolle ima- 

 gined they were root-buds, where adventi- 

 tious roots might arise under favourable 

 circumstances ; but this was an error. Du 

 Petit Thouars thought they were breathing- 

 pores, replacing the stomata of the epider- 

 mis; out they are not pores; and many trees, 

 such as the Conifers, Roses, Euonymus eu- 

 ropcBuSj &c., have none. 



BIBL. DeCand. Ann. Sc. Nat. 1826, vii. 

 6;Mohl, Vennischt.Schnft. 229, 233 ; Meyer, 

 Linncea, vii. 447; linger, Flora, 1836, ii. 

 577 ; St. Pierre, Compt. Rend. 1855 ; Ann. 

 N. H. 2 ser. xvi. 273. 



LEPADEL'LA, Bory. A genus of Ro- 

 tatoria, of the family Euchlanidota. 



Char. Eyes absent ; foot forked. 



Three species. 



L. emarginata (PI. 43. fig. 43). Carapace 

 depressed, oval, anterior portion broad, 

 emarginate at each end. Freshwater; 

 length of carapace 1-570". 



Teeth of L. ovalis, PI. 43. -fig. 44. 



BIBL. Ehr. Infus. p. 457. 



LEPEOPHTHI'R U S,Nordm. A genus 

 of Crustacea, of the order Siphonostoma, 

 and family Caligidae. 



Char. Fourth pair of legs slender, not 

 branched, formed for walking ; thorax with 

 only two distinct joints ; frontal plates 

 destitute of sucking-disks on the under sur- 

 face. Six British species, found upon 



various marine fishes, as the salmon, mac- 

 kerel, sole, brill, turbot, &c. 



L. pectoralis (PL 19. fig. 23). 



BIBL. Baird, Brit. Entomost. p. 273. 



LEPERDITIA, Rouault. An extinct 

 bivalve Entomostracan, probably Ostra- 

 codous ; bean-shaped ; smooth ; straight 

 on the dorsal, convex on the ventral 

 margin; smaller in front than behind; 

 right valve overlapping the left along 

 the ventral edge ; each valve bearing a 

 pitted and radiate muscle-spot and an 

 ocular tubercle. The dorsal region of the 

 left valve is swollen in some species. 

 Fossil only. 



30 Silurian species, 6 Devonian, and 14 

 Carboniferous, with many varieties. 



BIBL. Jones, Ann. N. H. 2 ser. xvii. 81 ; 

 5 ser. ix. 168 ; M. Mic. Jn. iv. 184. 



LEPIDOCYR'TUS, Latr. A genus of 

 Thvsanura. 



L. curvicollis is one of the insects which 

 yield the so-called Porfwra-scales. The 

 first segment of the thorax is as long as the 

 two next, and projects so as to cover the 

 neck and part of tlie head. It is found under 

 stones or old wood. See PODUBA. 



LEPIDOP'TERA. An order of Insects, 

 consisting of butterflies and moths. 



Lepidopterous insects present several 

 points of interest to the microscopic ob- 

 server ; among these may be mentioned 

 especially the proboscis or ANTLiA,the hook 

 connecting the wings (INSECTS, p. 432), the 

 wings themselves, and the beautiful scales 

 covering them (SCALES OF INSECTS, TEST- 

 OBJECTS). Their larvae or caterpillars are 

 favourable subjects for the examination of 

 the internal structure the tracheae with 

 their spiracles, the fatty body, the alimen- 

 tary canal, the spinning organs, the curious 

 legs, &c. 



LEPISMA, Linn. A genus of Thysa- 

 nurous Insects, family Lepismenae. 



Char. Body elongated, flattened; antennae 

 setaceous, with numerous very short joints ; 

 palpi four, long ; abdomen terminated by 

 three long filaments jointed near their 

 ends. 



L. saccharina (PI. 35. fig. 18). Body 

 silvery-grey, not spotted, covered with 

 scales ; caudal filaments speckled with 

 reddish brown ; antennae about two-thirds 

 the length of the body. 



This active little insect, which runs but 

 does not jump, is found (in the country) 

 upon the shelves of cupboards where sweets 

 and other eatables are kept, in window- 



