COLLEMACEI. 



[ 193 ] 



COLLOSPH Ji:RA , 



species ; of whicli 27 are found on earth, 

 rocks, trees, See. iu Great Britain. 



BiBL. Xylander, Si/n. 101, pis. 2,3,4; 

 Lei-iliton, Lic/i. Fl. 1879, 15. 



COLLEMACEI.— A family of Lichens, 

 having a gelatinous tliallus ; compris-ing 

 the tribes LIC^E^■El and Collemei, which 

 see. 



COLLEMEI. — A tribe of gelatinous 

 Lichens, fam. Collemacei, with a membra- 

 nous lobate thallus. 



Gen. Pjfrenoiisis, Sijnalissa, Collema, Lep- 

 tof/iutn, Collemopsk, and Pi/renidhwi. 



"COLLEMOP'SIS, Nyl.-A genus of Col- 

 lemaceous Lichens, with the thallus glau- 

 cous-green internally. 7 British species. 



BiBL. Leighton, Lich. Fl. 35. 



COLLEXt'HYMA.— A peculiar kind of 

 thickening of celkdar tissue iu the subepi- 

 dermal layers of many herbaceous stems, 

 such as limner, Beta, Chenopodiiim, &c. ; 

 which some have regarded as intercellular 

 substance, while others, more correctly, have 

 stated it to consist of metamorphosed se- 

 condary layers inside the cells. See Inter- 

 cellular SuBST.AJvCE. 



COLLETONE'MA, Brebisson.— A genus 

 of Diatomace8e. 



Char, 



Frustules navicular, sigmoid or 



straight, arranged in rows, and immersed 

 in a gelatinous mucus, forming a filiform 

 frond. Fresh water. 



C. eximiimi. Valves sigmoid ; length 

 1-340". 



C. vulgare. Valves elliptic-lanceolate, 

 slightly contracted at ends ; length 1- 

 410". 



C. neqlectum. Valves elliptic-lanceolate ; 

 length i-250". 



6'. suhcohcerens = Micromega suhcohce- 

 rens. 



Three other species, C. viridulum, C. la- 

 custre, and C.Jle.vile. 



Rabenhorst aiTanges these in a section of 

 the genus Sckizonema, 



BiBL. Smith, Brit. Dial. ii. 69; KUt- 

 zing, Sp. Alg. 105 ; Rabenhorst. Fl. Alg. 

 i. 265. 



COLLOID MATTER, exudation and 

 CORPUSCLES (animal). 



The term colloid matter or exudation is 

 applied to a transparent, viscid, yellowish, 

 structureless or slightly granular matter, 

 resembling liquid gelatine, arising from the 

 metamorphosis of the protoplasm of the 

 cells. It occm-s as a normal and a patho- 

 logical product. In a state of greater con- 

 sistence, it sometimes forms flakes or irre- 



gular masses, which occasionally possess a 

 laminated structure. In a third form it 

 constitutes spherical, rounded or oval, 

 sometimes flattened microscopic corpuscles 

 — simple masses of sarcode (Pi. 38. flg.22«). 

 These are either homogeneous, or exhibit 

 numerous laminte (concentric colloid cor- 

 puscles) (PI. 38. fig. 22 h) : sometimes a 

 kind of nuclear body is present (fig. 22 c); 

 at others they contain carbonate and phos- 

 phate of lime (fig. 22 cZ). Sometimes they 

 exhibit a radiate appearance (fig. 22 e). In 

 the liquid form, colloid exudation is found 

 ■within cysts iu the thymus and thyroid 

 glands, the ovary, &c., and within the en- 

 larged areolae of areolar tissue around these 

 organs, &c. It is found in a free state upon 

 the surface of inflamed serous membranes. 



The colloid corpuscles are met with in 

 the hypertrophied heart, in the prostate, the 

 thyroid, and the thymus glands, in the 

 choroid membrane, in the brain and spinal 

 cord, and iu the (waxy) spleen, &c. 



The liquid colloid matter is not precipi- 

 tated by acetic acid ; it becomes of a 

 gelatinous consistence, retaining its trans- 

 parency or turbid and opaque, by heat. 

 The colloid corpuscles do not, however, 

 appear to be uniform in composition : some- 

 times they consist of a proteine-compound ; 

 at others, doubtfully, of cellulose or amy- 

 loid, as iu the brain (true Corpora ahy- 

 lacea). These bodies are further noticed 

 under the heads of the tissues and organs 

 in which they occm*. See also Tumours 

 {Colloid cancer). 



BiEL. Rokitansky, Path. Anut. 1. 304; 

 Wedl, Path. Histol. ; Forster, Hand. spec. 

 Path. ; Virchow, Arch. Path. Anat. v. ; 

 Rindfleisch, Path. Gexvehelehre, 29 ; Green, 

 Pathol. Sf-c. 57. 



COLLO'MIA, Nutt.— A genus of Pole- 

 moniaceas (Dicotyledons) remarkable for 

 the spiral structures produced in the epi- 

 dermis of the seeds (PI. 28. fig. 22) (see 

 Spiral Structures). The gummy sub- 

 stance in which fibre is imbedded is solu- 

 ble iu water and not in spirit ; therefore 

 the best way to observe the elastic opening 

 of the spiral fibres is to make fine sections 

 of the coat of the seed and place them in a 

 little spirit of wine, 'upon a slide, with a 

 covering glass, to adjust the focus, and 

 then to add water carefully at the side of 

 the covering glass so as to wash away or 

 dilute the spii-it. 



COLLOSPILFIRA, Mlill.— A genus of 

 Radiolariu, fam. Thalassicollidae. 



o 



