CHLOROGONIUM. 



[ 137 ] 



CHLOROPHYLL. 



Lichens (Lepraria), it will still differ from 

 the plants we have assembled under the 

 name of Protococcus, in its general habit, 

 especially in the absence of zoospores. This 

 point is, however, still open to inquiry, since 

 from recent investigations it appears that the 

 gonidia of the Lichens do divide into two, 

 four and eight, to form a pulverulent stra- 

 tum, which exactly represents Chlorococcum 

 and Protococcus. 



Chi. vulgare, Grev. (PI. 3. fig. 1). A 

 collection of extremely minute cells, multi- 

 plying by division into twos and fours, no 

 gelatinous substratum, no zoospores. Dia- 

 meter of single cells 1-3000 to 1-4000" 

 (Protococcus viridis, l-200()to 1-3000"). Old 

 dry palings, bark of trees, &c., every- 

 where. Calculating from the known size of 

 the cells and the wide distribution, this, if a 

 species, would appear to be the most fecund 

 Alga in existence. There are 300 millions of 

 individuals on a square inch, in a layer 1-100" 

 thick, and such layers clothe almost every 

 piece of unpainted timber and old trunk we 

 meet with in the country. C. murorum, Gr. is 

 perhaps a Palmoglcea, Kiitz. 



BIBL. Greville, Sc. Crypt. Fl. pi. 262; 

 Hassall, Br. Fr. Alga, pi. 81. fig. 5. 



CHLOROGONIUM, Ehr. A genus of 

 Infusoria, of the family Astasiaea. 



Char. A red eye-spot, a tail, and two 

 anterior filaments. (Not attached by a fixed 

 pedicle.) 



C. euchlorum (PI. 23. fig. 31). Spindle- 

 shaped, acute at each end, tail short ; length 

 1 - 1 1 50 to 1 -280 ''. Found in enormous numbers 

 in pools and puddles ; frequently as many as 

 10,000 in a single drop. 



These organisms do not admit colouring 

 matter or foreign bodies ; hence they are 

 probably not Infusoria, but Algae. They 

 often adhere to each other in groups by the 

 so-called tails (PL 23. fig. 31, upper figure) ; 

 sometimes to foreign bodies (PI. 23. fig. 31, 

 lower figure, which exhibit them adhering to 

 a dead Vorticelld). 



They undergo oblique spontaneous divi- 

 sion (PI. 41. fig. 1) ; this commences in the 

 internal substance, which is constricted before 

 the outer portion. 



They also propagate by a process of 

 swarming, which takes place thus : the 

 internal substance first separates somewhat 

 from the transparent wall, subsequently 

 becoming irregularly constricted at various 

 parts. The constrictions deepening, the con- 

 stricted portions separate from each other as 

 independent vesicles (?), and the internal 



substance acquires the appearance of a black- 

 berry or bunch of grapes; consisting of a 

 fusiform aggregation of uniform longish oval 

 granules. Up to this period, the parent 

 organism continues its movements; subse- 

 quently these cease. The granules have now 

 acquired independent vitality, and their fila- 

 ments become developed. The envelope 

 then breaks near its middle, and the swarm 

 of young ones escapes. In their somewhat 

 more developed stage they form Glenomorum 

 tingens, Ehr. See PROTOCOCCUS. 



BIBL. Ehr. In/us, p. 113; Weise, Wieg- 

 mann's Archivf. Naturgesch. 1848. i. p. 65; 

 Stein, Die In/us, p. 188 et seq. 



CHLOROPHYLL (leaf-green). The 

 name applied to the green colouring matter 

 of plants. The nature of the bodies which 

 are understood under this term is still 

 somewhat questionable. It is ordinarily 

 stated that chlorophyll exists commonly 

 under the form of globules or granules, and oc- 

 casionally as an amorphous granular substance, 

 in either case more or less adherent to, or 

 imbedded in the primordial utricle of the 

 cell. It is, however, a contested point 

 whether the chlorophyll-corpuscles are semi- 

 solid, homogeneous globules, or vesicles 

 composed of a delicate membrane enclosing 

 a green liquid. Chlorophyll presents itself 

 in the form of distinct corpuscles (granules 

 of authors), in the cells of the flowering 

 plants generally, particularly the parenchyma 

 of leaves and the subepidermal parenchyma 

 of green stems and shoots. The granules are 

 especially large and distinct in certain water- 

 plants, and may be well seen lying scattered, 

 singly, imbedded in the circulating protoplasm 

 of the cells of the leaves of Vallisneria and 

 other water-plants. The corpuscles are 

 very clear in the cells of the prothallia of 

 Ferns, in the leaves of Selaginella, of Mosses 

 and Liverworts ; also in Chara, where they 

 are very abundant, and form a continuous 

 layer, or else numerous rows, imbedded in a 

 gelatinous stratum, between the cell-wall and 

 the circulating mass of protoplasm. In the 

 Confervoids the chlorophyll often appears 

 both formless and corpuscular in one and the 

 same cell, but usually more or less formless 

 in young cells, and more completely con- 

 verted into granules in the full-grown, as in 

 Vaucheria. In the Confervacese, such as Cla- 

 dophora, (Edogonium, it presents itself in a 

 granular stratum with numerous larger bright 

 corpuscles, and in Spirogyra, Zygnema, &c., 

 the chlorophyll takes the form of the spiral 

 or annular band, to which it is adherent, 



