CLIMACOSniEXIA. 



[ la-^ ] 



CLOSTERIUM, 



2 ."calariform dissepiments ; valves striato- 

 puuotatc^, costoe none. 



C. Lorenzii. Yahes linear-lanceolate, 

 swollen at the ends and the middle. In the 

 Adriatic. 



BiBL. Grimow, Wien. Verhandl. 18G2, 

 421, pi. 8. fiff. 7. 



CLLMACbSPHE'NIA, Ehi-.— A genus 

 of Diatomaceoe. 



Char. Frustules cuneate, stipitate, di- 

 vided into loculi by transverse septa ; valves 

 obovato-lanceolate, vrith moniliform vittae 

 in the front view. Marine ; not British. 



C. australis. Very shortly stipitate ; sides 

 of the valves not (very faintly ?) striated. 



On Algce from New Holland and South 

 Africa. 



C. monilicjera (PI. 25. fig. 9). Stipitate, 

 sides of tlie valves transversely striated {a, 

 front view ; b, side view). 



In the Gulf of Mexico. 



Rabenhorst enumerates 6 species. 



BiBL. Ehrenb. Abh. Berl Ak. 1841, 401 : 

 id. Ber. 1843 ; Kiitzing, BaciUar. 123, and 

 Sp.Alq. 114; Rabenhorst, Alg. i. 299. 



CLIMACOS'TOMUM, Stein, = S^nrodo- 

 miim virens, Ehr. 



CLI'OXA, Gi"ant. — A genus of marine 

 Sponges. By means of the spicula imbedded 

 in their surface, they burrow into rocks, 

 shells, and stones. 



BiBL. Gosse, Mar. Zool. i. 5 ; Hancock, 

 Ann. Nat. Hist. 1849, i. 321 ; Bowerbank, 

 Brit. Spoq. ii. p. 212. 



CLONOS'TACHYS, Oorda.— Agenus of 

 Mucedines (Hyphomycetous Fungi), appa- 

 rently not distinct from Botrytis. 



C. araucaria (fig. 347) has been found in 

 Enirland. 



BiBL, Corda, Prachffl. europ. Schimmel- 

 bi/cl pi. lo ; Currey, Qu. Mic. Jn. v. 126. 



CLOSTE'RIUM, Nitzsch.— A genus of 

 Desmidiacea? (Confervoid Algae). 



Char. CeUs single, elongated, attenuated 

 towards each end, entire ; mostly curved 

 Innately or arcuate ; junction of the seg- 

 ments marked by a pale transverse baud. 

 Endochrome green. 



This beautiful genus is of great interest to 

 the scientific microscopic observer. Many 

 of the species are veiy common, so that 

 scarcely a drop can be taken from the bot- 

 tom of a clear pool without some of them 

 being contained in it. 



Each cell is composed of two equal por- 

 tions, uniting at a transverse line occupying 

 the middle of the cell. The endochrome 

 exhibits longitudinal bands (PL 14. fig. 40), 



the number varying in different species, of 

 a darker green thau the rest of the endo- 

 chrome (PL 14. figs. 40, 41, 43). A num- 

 ber of chloropliyll-vesicles are frequently 

 visible in the endochrome, sometimes scat- 

 tered irregularly, at others arranged in lon- 

 gitudinal series (PL 14. fig. 43) ; at certain 

 periods these contain starch-granules. 



The green endochrome is separated from 

 the cell-wall by a stratum of colourless pro- 

 toplasm which occupies a bluntly triangular 

 space at each extremity. In many cases 

 the protoplasm at these ends exhibits a 

 large roundish vacuole, in which a number 

 of minute granules are contained, often in 

 active motion. Similar granules are visible 

 in the marginal line of protoplasm, which 

 exhibits a distinct circulation, requiring a 

 power of about 403 to show it clearly. 

 Focke, Osborne, and others have described 

 cilia inside the cell-wall, and attributed the 

 circulation to their action ; but this is erro- 

 neous. The protoplasm appears to flow up 

 over the interior of the cell-wall on all 

 sides, from the centre to the extremity, 

 then to turn round past the vacuole, and 

 return over the surface of the green endo- 

 chrome parallel to the upward course. 

 Wills states that the vacuoles at the ends 

 of the cells are contractile vesicles, con- 

 nected with the flow of the currents. 



The Closteria are reproduced in various 

 ways. The individuals divide, like the re.-t 

 of the Desmidiacese, the separation taking 

 place transversely in the situation of the 

 transparent space, where two new half-cells 

 become developed, subsequently separating. 

 As tliese new ' halves' are often very small 

 at the epoch of separation, specimens occur 

 with the two portions very unequal. 



Another mode of reproduction is by con- 

 jugation. In this, a pair of individuals be- 

 come united somewhat in the same way as 

 in the Zygnemaceoe ; ordinarily the indi- 

 viduals conjugate by the convex side. The 

 process is this : — The outer membranes of 

 the parents split circularly in the situation 

 of the central transverse space ; a delicate 

 internal membrane is protruded from each 

 as a sac, and these meet and coalesce. 

 Sometimes the sacs are in paii's from each 

 parent-cell. (See Conjugation.) When 

 the cross process is complete, the contents 

 of both parent-cells pass into it and become 

 collected iuto a globular or squarish cell or 

 zygospore (PL 14. tigs. 42 & 46.). Dif- 

 ferent statements are made with regard 

 to the ultimate history of this; and it is 



