INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 319 



towartls the light. Among the former he includes the swarmspores 

 of Hcematococcus and Bryopsis ; among the latter the gametes of 

 Botrydium. Stahl has repeated the experiments with the gametes or 

 conjugating swarmspores of Botrydium, but is in this particular unable 

 to confirm Strasburger's statements. He finds that, like typical 

 swarmspores, they are photometric. 



The same tendency to place the two extremities alternately towards 

 the incident light was observed also with fixed individuals of Euglena. 



Palmelline and Characine in Fresh-water Algae.* — Since the 

 publication of his note on PahnelUne,-f Mr. Phipson has found that 

 if, before extracting palmelline, Palmella cruenta is soaked for twenty- 

 four hours in bisulphide of carbon, the liquid becomes a golden yellow, 

 and leaves, on evaporation, a yellow substance with a little earthy 

 matter. This yellow substance appears to be xanthophyll (the 

 yellow colouring matter of autumn leaves), as it dissolves in concen- 

 trated sulphuric acid, giving an emerald green solution. When the 

 bisulphide of carbon has been separated, alcohol extracts all the 

 chlorophyll, and when the alcohol has been completely driven off and 

 the plant dried at the ordinary temperature, the water with which it 

 is to be covered becomes in a few hours charged with palmelline ; 

 three substances being thus successively extracted from one micro- 

 scopic Alga which to the eye seems to be blood-red. 



In addition there is found in small quantities another very interest- 

 ing product — Characine (so called on account of its very pronounced 

 marshy odour like Cliara). This is a substance lighter than water, a 

 species of camphor, which forms very small pellicles on the surface, 

 but only dissolves in extremely small quantities. If Palmella, Oscillaria, 

 Nostoc, &c., are dried in the air and afterwards covered with cold water, 

 the liquid, in eight to ten hours, will show on its surface some thin 

 and often iridescent layers. The liquid should be pcxu-ed ofi'lnto a long 

 narrow tube and shaken up with some cubic centimetres of ether, which 

 dissolves the characine, and leaves it, on evaporation, as a white greasy 

 substance, volatile, inflammable, non-saponific, soluble in alcohol and 

 ether, almost insoluble in water, and possessing a strong marshy smell 

 which is very characteristic and which it communicates to the water. 

 After a few days it volatilizes, or rather disappears by oxidation from 

 the surface of the water, which completely loses its marshy odour. This 

 odour, so strongly developed in Chora, is due to this substance, which 

 is formed by the plant itself diu-ing life, and is not a product of 

 decomposition. Characine is met with in all the terrestrial Alga^, 

 such as Palmella, Vaucheria, Anahwna, Oscillaria, &c., and in the 

 Conferva;. 



Structure of Spirulina.J — The species of this genus resemble 

 the other genera of Oscillatoriea), to which it belongs, in consisting of 

 cylindrical segmented threads containing phycochrome, and in being 

 invested with a mucilaginous envelope ; but they arc jxjculiar in 



* 'Comptcs RondiiH,' Ixxxix. (1870) p. Ki'S. 



t Ibid., p. :ilG. iiiid wi- tlii.s .loiirn. ii. (IST'J) p. 938. 



; 'OcHtcrr. IJc.t. Zoitsolir.,' xxx. (1.^80) ],. II. 



