LECYTHEA. 



[ 382 ] 



LEMANIE.E. 



somewhat concave, adnate, covered by a 

 black membrane, the disk at length tuber- 

 cled, with a border of its own substance. 



LECYTHEA, LeV. See UREDINE^B. 



LEECH. Two species of the genus Hi- 

 rudo, which belongs to the class Annulata, 

 are used for medical purposes, viz. H. medi- 

 cinalis, in which the ventral surface is green- 

 ish, with black spots ; and H. officinalis, in 

 which these spots are absent. 



The structure of the mouth of the species 

 of Hirudo is curious. The mouth is trian- 

 gular (PI. 17. fig. 25), and placed in the 

 middle of the anterior sucker. Each of its 

 three sides is furnished with a semicircular 

 jaw of cartilaginous consistence (fig. 26, side 

 view; fig. 27, view from above), upon the 

 convex margin of which are placed a large 

 number of partly calcareous teeth (fig. 26 b) 

 arranged in a row. The teeth (fig. 28, a side 

 view, b view from above) are flattened, some- 

 what triangular, and excavated at the base, 

 so as to exhibit two short prongs (d). They 

 are placed transversely upon the jaws, which 

 are moved by powerful muscles, and thus 

 produce the well-known wounds. And this 

 cross direction of the teeth is probably the 

 cause of the troublesome bleeding accompa- 

 nying the bite of a leech, in consequence of 

 the amount of laceration necessarily con- 

 nected with it. 



The species of Hirudo have ten minute 

 eyes, arranged in the form of a horse-shoe 

 at the upper part of the anterior sucker. 



The ova of leeches are deposited in a kind 

 of cocoon, composed of triangular fibres, 

 branched and interwoven so as to bear con- 

 siderable resemblance to a sponge, as which 

 one of them was formerly described. 



BIBL. Brightwell, Ann. Nat. Hist. 1842. 

 ix. 11; Brandt and Ratzeburg, Mediz. Zoolog. 

 ii. ; Johnson, Treatise on the Medicinal 

 Leech, and Further Observ., fyc. ; Moquin- 

 Tandon, Monographie d. Hirudinees, &c. ; 

 Savigny, Descript. de VEgypte, xxi. ; Au- 

 douin and Milne-Edwards, Classif. des An- 

 nelides, 8fc. in Ann. d. Sc. nat. 1832-3, 27- 

 30 (separately printed); Bowerbank, Ann. 

 Nat. Hist. 1845. xv. 304 ; R. Jones, Outl. 

 of Animal Kingdom, p. 192. 



LEIBLEINIA, Endl. A genus of ma- 

 rine plants, placed among the Ectocarpacese 

 by Endlicher, and among Oscillatoriacese 

 (Confer void Algae) by Kiitzing, who includes 

 under it many of the species of Calothrix of 

 other authors. Endlicher cites only C. con- 

 fervicola, Ag., and another not British. 



This is a minute, glaucous, tufted plant, 



formed of short, rigid, erect, subulate fila- 

 ments, and is common, epiphytic on marine 

 filamentous Algae. 



BIBL. Endl. Genera Plant. Supp. iii. 

 No. 69 ; Kiitzing, Sp. Alg. 276 ; Harvey, 

 Phyc. Brit. p. 223. pi. 26 C. 



LE JEUNIA, Libert. A genus of Junger- 

 mannieae (Hepaticaceae), containing several 

 rare British species, found in subalpine di- 

 stricts, viz. L. serpyllifolia, hamatifolia, mi- 

 nutissima, and calyptrifolia. The last is one 

 of the smallest of the British Jungermannieae, 

 and is remarkable for the peculiar form of 

 its leaves, which resemble the calyptra of a 

 moss (figs. 396, 397). 



Fig. 396. 



Fig. 397. 



Lejeunia calyptrifolia. 



Fig. 396. Stem with calyptriform leaves, an immature 

 plant (on the right), and a burst sporange. 

 Magn. 5 dianis. 



Fig. 397. A leaf of ditto. Magn. 25 diams. 



BIBL. Hook. Brit. Jung. pi. 42. 43. 51. 

 52, Brit. Flora, ii. pt. 1. p. 127. 



LEM ANIE^E .A family of Confervoidese . 

 Olive-coloured freshwater Algae, filamentous, 

 inarticulate, of cartilagineo-coriaceous sub- 

 stance, and compound cellular texture. The 

 fronds branched, hollow, bearing within at 

 irregular distances whorls of wart-like bo- 

 dies consisting of tufted, simple or branched 

 necklace-shaped filaments (fig. 398), arising 



Fig. 398. 



Lemania torulosa. 



Section of filament, showing the tufts of fertile filaments. 

 Magn. 50 diams. 



from the inner wall of the tubular frond, 



