1880.] 



MICROSCOPICAL JOURNAL. 



156 



paes into the cavity of the ball, 

 gather around the female cells (ma- 

 crogonidia) and become fused with 

 them, which then become surroun- 

 ded with an envelope with conical, 

 pointed projections ( Volvox stella- 

 tus Ehr.), The chlorophyll is 

 then replaced by starch and red or 

 orange colored oil. 



v. Glohator, Ehr. (with V. au- 

 reus^ V. stdlatus, and SpTuBrosira 

 volvox, Ehr.) Ball as large as 0.65d. 

 Common, generally single, at times 

 very abundant in undisturbed 

 ponds. 



IL Gen. Pandorina, Ehr. {Bo- 

 tryocystis, Ktz.) Individuals pressed 

 close together, and therefore angu- 

 lar, surrounded with a common, 

 thick, gelatinous envelope, which, in 

 old colonies becomes double. Mul- 

 tiplication takes place by the break- 

 ing up of the colony, rounding of 

 the gelatin about the single indivi- 

 duals, and repeated division within. 

 Generally the individuals within the 

 mother cell, move asunder, become 

 rounded, and the whole assumes the 

 form of a mulberry. 



P. inoru'in, Bory. {Botryocystis, 

 volvox, Ktz.) 



Ball 0.2-0.25d. In stagnant 

 water, common, sometimes very 

 abundant. 



P. elegans, Duj. {Eudorina d^- 

 gans, Elir.) Individual with pigment 

 spot. Balls 0.04-0.125d. 



Ill Gen. StephmisophdBra, Cohn. 

 Eight spherical, or spindle, or cylin- 

 dric-shaped individuals, in spherical 

 gelatinous envelope. By three times 

 repeated binary division of each 

 individual, eight new families are 

 produced, which swarm out of the 

 old envelope. In other cases the 

 binary division continues further 

 and there result numerous small, 

 spindle-shaped bodies, each with 

 four Ulanients (spermatozoa or mi- 

 crogonidia), which finally swarm 

 out. From other colonies, indivi- 



duals swarm out without having 

 undergone division. These cannot 

 be distinguished from Chlamido- 

 monas. 



St. pluvialis, C. Balls 0.1-0.15. 

 In small puddles, on stones, etc. 



lY. Gen. Gonium, Miill. Fami- 

 lies of 16 egg-shaped, green indivi- 

 duals, with red stigma, in quadran- 

 gular, tabular gelatin. Movement 

 of the colony jumping. 



By four times repeated binary 

 division, 16 daughter colonies arise 

 from one old one, which finally be- 

 come separated and independent. 

 Sometimes the individuals swarm 

 out apparently to pass into the 

 resting condition. The vacuoles 

 (2, rarely 3) lie close under the 

 place where the cilia arise. 



G.pectorale, M. Individuals 0.006 

 -0.02d., tables 0.025-0.058. Com- 

 mon, particularly in green water. 



y. Gen. CKLamidoTnonas, Ehr. 

 {Diselmis, Duj., ChlamidocoGCuSy 

 A. B.) Individuals egg-shaped or 

 spherical, greenish or red, with red 

 stigma, not united in colonies. 



Ch. pluvialis, A. B. Usually 

 appears in abundance in the spring, 

 to disappear quite as suddenly, in 

 Summer no trace of it can be found. 

 The multiplication of these cells 

 (zoogonidia A. B.) takes place by 

 simple or twice repeated division. 

 Sometimes the division is continued 

 further ; then result smaller indivi- 

 duals (microgonidia, A. B.)of diffe- 

 rent form. After several weeks, 

 the originally elongated cells be- 

 come spherical, and pass into a rest- 

 ing condition. Their green condi- 

 tion. Their green contents become 

 brown, and colored drops of oil 

 appear within. 



EDITORIAL. 



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