-\'2 1' r i 1 s (• li . Stuclies oii Cyiuiophyceae. 



(Hl) ExDsporc und riulosporu of llu' .•sporc are merely llic 

 fully developecl coU-sheatli and inner investment resi^ectively. 

 l»otli of ^vhi('ll in tlie mature condition completely envelope the 

 })rotoplas;t. This does not agree witli ])revious accoiints of" tlic 

 devclopmont of tlio spore. In tlio spore of an Anahaota \ve 

 lind the same strueture of tlic investment reoccuiTing, as we 

 get in OJococapua etc. 



(IV) In OscÜlaria the transverse septa are less developed 

 tlian in Anahaena and consequently the cell-sheatli is not split 

 during division, but forms a coherent whole ronnd the entire 

 lilament. Its composite character is still indicated by a sHght 

 constriction at each transverse septum. 



(V) The sheath of an O.scil/aria and Lyiighya are two enti- 

 rely different structiires, the former as just stated being the 

 coherent cell-sheath, whilst the latter is homologous with the 

 external mucilage of Anabaena etc. Within this latter sheath 

 the filaments of Ly}igh!ja j^resent a structure, identical with that 

 of Oscillaria. 



(VI) In Tohjpoflirix and Eivularia on the other hand the 

 actual filament (within the external sheath) is provided with a 

 cell-sheath, whieh is only in part coherent and shows a very 

 marked moniliform strnctiu'e. 



(VII) The interceUular protoplasmic connections of many 

 observers are due to changes, produced in the gelatinous trans- 

 verse portion of the inner investment during staining. Proto- 

 plasmic connection is unnecessary, as diffusion can probably 

 take place tlirough the cell-membrane. 



University College London 

 September 20*'^ 1904. 



Keferences to Literature. 



Bornet et Flaliault: Revision des Nostocacees lieterocystees etc. (Ann. 



Sei. Nat. Ser. VII. T. III. etc. 1886.) 

 Borzi: Note alJa morfologia e biologia delle Alghe ficochromacee. (Nnovo 



giorn. botan. ital. Vol. 10. 1878. p. 236). 

 Borzi: Le comnnicazioni intracellulari delle Nostocliinee. ("Malpigliia. Ann. 



I. 1886. p. 74 et seq.) 

 Brand: Der Formenkreis von Gloeocapsa alpina l^äg. (Botanisches Centralbl. 



Bd. LXXXIII. 1900.) 

 Brand: Morpliologiscli - pliysiologisclie Betrachtungen über Cyanophyceen. 



(Beiliefte z. Botan. Centralbl. Bd. XV. 1908. Heft 1.). 

 Brand: Über das osmotische Verhalten der Cyanophj^ceenzelle. (Ber. 



Deut.. Bot. Ges. Bd. XXI. 1903. Heft 6. p. 302.) 

 Correns: Über die Membran und die Bewegung der Oscillarien. fBer. 



Deut. Bot. Ges. Bd. XV. 1897. p. 139). 

 Dangeard: L'autophagie sexiielle. (Le Botaniste. Ser. VI. 1899.) 

 Fritsch: Studies on Cyanophyceae. I. Some points in the structure of an 



Anabaena. (The New Phytologist. Vol. III. 1904 Nr. 4.).. 



