ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 55 



BOTANY. 



GENEHAL, 

 Including the Anatomy and Physiology uf Seed Plants. 



Cytology, 

 including' Cell-Contents. 



Study on Synapsis and Reduction.* — I. Cardiff has examined the 



mitoses iu the sporogeuous tissue of Acer Flatanoides, SaJomonia hiflora, 

 Gliikgo hiloha, and Botrychiuni ohliquum, and is led to the following 

 conclusions. The synaptic knot is a constant morphological character 

 of the mother-cell, and is always in contact with the nucleolus. Its 

 position is probably due to gravity. The nucleus increases in size up 

 to the time of synapsis, and there is a marked difference in the appearance 

 of the pre-synaptic and post-synaptic chromatin. Prior to synapsis the 

 chromatin forms into threads, which arrange themselves in pairs longi- 

 tudinally, move together, and finally fuse during synapsis. In this 

 fusion the chromomeres generally fuse in pairs, but there is probably 

 not a complete intermingling of chromatin in the bivalent thread. The 

 latter splits longitudinally iu the first mitosis, probably along the hue of 

 previous fusion. 



Synapsis is a stage of great chemotactic activity, and may be regarded 

 as the end result of fertilisation. The author thinks that in fertiHsation 

 there is a nuclear, but not a chromatin fusion, but that the paternal and 

 maternal elements retain their identity throughout the sporophytic 

 existence of the plant, finally fusing during synapsis. 



Phycocyanin.t — H. Molisch exposes the erroneous theory that 

 Cyanophyceffi all possess one and the same phycocyanin, and shows 

 that there are at least three, and probably more phycocyanins. They 

 represent very closely-allied albuminous bodies, which are, however, 

 easily distinguished from one another by the colour of their aqueous 

 solutions, the colour of their fluorescence, their power of crystallisation, 

 and their spectroscopic properties. The author gives instances of 

 Cyanophycefe which have the different forms of phycocyanin, and states 

 that though many factors undoul)tedly take part in the production of 

 the different colours of the alg^e of this group, there can no longer be 

 any question that one of these factors is tlie difference of phycocyanin. 

 An interesting note is made concerning Porphyridium crmntum Nageli, 

 which is found by the author to possess no phycocyanin, but only crystal- 

 lisable phycoerythriu. This is the only known instance of this colouring 

 matter in an aerial alga, and the discovery supports the views of Schmitz 

 and (laidukov as to the relationship between Porphyridium and the 

 Bangiales. 



* Bull. Torres- Bot. Club, xxxiii. (1906) pp. 271-306(4 pis.), 

 t SB. k. Akad. Wieu, csv. (1906) 2 pis. 



