LAOPIIOXTE. 



[ 453 ] LATICIFEROUS TISSUE. 



CJiar. Polypidom rooted, erect, jointed ; 

 the joint>i rinued and incrassate; cells alter- 

 nate, canipanulate, on short pednncles ; 

 vesicles axillary; embrj'os medusiforni. 



Six British species : dichatoma (ovicell, 

 PI. '-V^. fig. 4 c), geniculata, f/elafinosa, ob/iqua, 

 F/cminf/ii, and htcerata. Found upon marine 

 Alga?, stones, kc, between tide-marks. 



BiBL. Johnston, Br. Zooph. 101 ; Gosse, 

 Mar. Zool. ii. :24 ; Hincks, Br. Zooph. 



LAOPHON'TE, Philippi.— A genus of 

 Copepodous Entomostraca. Eight species, in 

 dredgings. (Brady, Copep., Bay Soe. ii. 70.) 



LAR, Gosse. — A geuus of Hydroid Zoo- 

 phytes. 



Char. Bodies fusiform, sessile, with two 

 tentacula springing from the base of a bilo- 

 bate proboscis, developed on a creeping and 

 anastomosing stolon. 



Lar saheUarum. The polypites bear a 

 close resemblance to the human figure. 



BiBL. Gosse, Linn. Tr. xxii. 113, tab. xx. ; 

 Hincks, Br. Zooph. 36. 



LAREL'LA, Ehr. — A genus of Rotifera, 

 fam. Brachionea. 



Char. Body with equal setre and three 

 long fine hairs on each side of mouth ; two 

 frontal eyes ; length 1-190 to 1-280". 



BiBL. 'Piitchard, Infns. 712. 



LARVx-E. — In animals which pass 

 throug-h certain marked stages of develop- 

 ment, or undergo metamorphosis, as it is 

 called, the condition in the first of these 

 stages is called the larval state, and the 

 animal itself is called a larva. 



The aquatic larvae of several insects are 

 well-known microscopic favourites on ac- 

 count of their transparence, which allows 

 the action of the dorsal vessels, with the 

 circulation of the nutritive liquid, to be 

 seen, and their curious respiratory organs. 

 A few of the more common aquatic larvse 

 and their parts are represented in PI. 35. 

 figs. 1, 14-17, 19-22, 29 ; these are noticed 

 more in detail imder their respective 

 heads. 



The aquatic larvae of some Amphibia are 

 admirable objects for exhibiting the circu- 

 lation of the blood, the deAelopment of 

 tissues, &c.. as those of the frog (tadpoles) 

 and of the Triton. 



LASIOB'OTRYS,Ktz.— A genus of Peri- 

 sporacei (Ascomycetous Fungi). 



L. Lonicerce grows on the living leaves 

 and stems of various kinds of Honeysuckle, 

 forming little heaps seated on a tuft of ra- 

 diating filaments. The so-called peridioles 

 appear to be sclerotioid bodies, the superfi- 



cial cells of which are converted into true 

 perithecia, becoming free on the surface : 

 these contain numerous asci when mature; 

 but the spores have not been observed. 



BiBL. Berk. Br. Fl. ii. pt. 2. 324 ; Ann. 

 N. H. 2 ser. ix. 386, pi. 12. fig. 44 ; Fries, 

 Sum. Veg. 406 ; Greville, Sc. Crypt. Fl. pi. 

 191. 



LASTRiEA, Presl.— A genus of Aspi- 

 diese (Polypodiaceous Ferns), now consoli- 

 dated with Nephrodium. 



LATEX.— The name applied to the pe- 

 culiar juices, becoming milky when ex- 

 posed to air, contained in the * milk-vessels,' 

 or laticiferous canals of plants, especially 

 abundant in Euphorbiacese, Papaveraceae, 

 Cichoracese, &c. It appears to consist of a 

 watery fluid, with albumen in solution, in 

 which float globules of caoutchouc, or analo- 

 gous gum-resinous matter, of variable size, 

 occasionally mixed with starch-granules of 

 peculiar forms, as in Euphorbia (PI. 48. 

 fig. 23). According to Sachs andHanstein 

 it is a fluid which contains matters of a 

 directly nutritive character and others which 

 are excrementitious in their nature. Trecul, 

 on the other hand, appears to consider that 

 the latex is the residue of the sap after 

 elaboration by the cells. See Laticiferous 



TISSUE. 



BiBL. Schultz, Vaisseanx latici feres d. 

 Plantes, 1841 ; Mohl, Bot. Zeit. 1843 ; Ann. 

 N. H. xiii. 441. 



LATHONU'RA, Lilljeborg.— A genus of 

 Cladocerous Entomostraca. 



CJiar. Carapace obovate, not produced, 

 ventral margin furnished with peculiar 

 flattened spear-shaped plates attached to 

 the edge. I Irish species. 



BiBL. Norman & Brady, Monogr., Nat. 

 Hist. Tr. Northumb. 



LATHR^A.— A genus of Orobancha- 

 ceous Flowering Plants. L. squamaria, a 

 remarkable plant, found here and there in 

 beech-woods in England, has been the sub- 

 ject of much research as regards embiyo- 

 logy, by Schacht and others. See Ovule. 



LATICIFEROUS TISSUE, ducts, ca- 

 nals, or VESSELS. — These names are applied 

 to the tubular and often ramified canals in 

 which the milky juice or latex of many 

 plants is contained (tigs. 388, 389). The na- 

 ture, or rather the origin, of these canals is 

 still a matter of dispute. The ducts present 

 themselves in various forms, especially in 

 the rind and pith of the Apocynacese, 

 Asclepiadacefe, Moraceae, Urtieaceae, Papa- 

 veraceae, Cucurbitace8e,Euphorbiaceae,Aroi- 



