ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 625 



macrozoospores with four cilia, and small ovoid or angular microspores, 

 on which no cilia were detected. The mode of reproduction could not 

 be followed. The following is the description of the new genus TricJio- 

 pMlus : — Fila articulata, irregulariter ramosa, in stratis tenuibus expansa, 

 amoene viridia ; fila singula late confluentia, ad apicem plerumque sensim 

 attenuata, reptantia. Eamuli uni- pauci-articulati, appendice radiciformi 

 destiti. Articuli vegetativi cylindracei, diametro sequali vel 1/2 latiore 

 longitudini, ad genicula leviter constricti, contento viridi, chromatophoris 

 exiguis, loculo centrali sine colore, granulis minutis circumdato ; mem- 

 brana hyalina, firma, duobus stratis constituta. Cellulsa vegetativ^e 

 intumescentes in zoosporangiis transmutantur. Propagatio agamica 

 macro-zoosporis et microsporis. Macro-zoosporse liberse ovatte, polo 

 antieo hyalino, ciliis quaternis vibrantibus instructse; contento viridi, 

 ocello rubro non viso. Microsporse contenti divisione succedanea repetita 

 ortse, 32 in quaque cellula, pariete matricali lateraliter ostiolo poriformi 

 aperto liberatte, macrosporis minores, ovatse v. angulatee et ciliis destitutte, 

 Verisimile statim porro evolventes, nee inter se discedeutes in thallum 

 transformantur. Propagatio sexualis adhuc ignota. 



The two other parasitic algae are violet, belonging to the family 

 Chamaesiphoneae, and forming a new genus named Cyanoderma, with 

 coccogonia, each of which contains a varying number of gonidia. The 

 following is its diagnosis : — Algee unicellulares, conidiis et cellularum 

 vegetativarum divisione sese multiplicantes. Cellulae vegetativee cum 

 coccogoniis in eodem thallo evolventes, contento homogeneo, colore coeru- 

 lescente violaceo, minutse, in pili substantiam penetrantes. Coccogonia 

 globosa aut subglobosa, membrana crassa circumdata, matura demum ad 

 apicem soluta. Conidia pauca aut numerosissima, et contenti divisione 

 in tres directiones angulis rectis sese secantes orta. Species omnes in 

 aere crescentes. 



Conjugation of Spirogyra.* — Herr C. E. Overton has followed the 

 course of the process of conjugation in Spirogyra, especially in S. decimina 

 and nitida. He finds the most convenient fixing material to be chromic 

 acid and its compounds, or picric acid, and the preparation was then 

 stained with an alcoholic solution of borax-carmine, treating afterwards 

 with a • 1-0 • 5 per cent hydrochloric acid in 70 per cent, alcohol. 



In ;S^. Weheri, with a diameter of 24:-28 /x, the conjugating processes 

 approached one another with a rapidity of about 3 ju, in the hour. After 

 contact, it takes twenty-four hours for them to become firmly attached to 

 one another, and for the separating wall to become absorbed. The 

 author believes that, during their growth, a substance is exuded from the 

 processes by which the direction of their growth and their ultimate 

 meeting is brought about. The development of the processes does not 

 appear to be always caused by their mutual action on one another, as a 

 cell is sometimes found to put out one of great length, which does not 

 unite with any other cell. In many species the sexual nature of the cells 

 can only be regarded as relative, not absolute, as is shown by the occur- 

 rence of lateral conjugation. This frequently takes place with groups 

 of four cells, of which the two central ones are of the same sex. 



The passage of the contents of the male cell, which usually takes 

 place at night, is a purely physical process. By the use of the method 

 mentioned above, and examining in xylol or Canada balsam, it is easy to 



* Ber. Deutsch. Bot. Gesell., vi. (1888) pp. 68-72 (1 pL). 



