212 
F r i t s c li, Stndies on Cyanopliyceae. 
(III) Exospore and endospore of tlie spore are merely the 
fully developed cell-sheath and inner investment respectively. 
botii of which in the matnre condition completely envelope tlie 
protoplast, This does not agree with previous acconnts of tlie 
development of the spore. In the spore of an Anabaena we 
hnd the sarne strnctnre of the investment reoccnrring, as we 
get in Gloeocapsa etc. 
(IV) In Oscillaria the transverse septa are less developed 
phan in Anabaena and consequently the cell-sheath is not split 
during division, but forms a coherent whole ronnd the entire 
filament. Its composite cliaracter is still indicated by a slight 
constriction at each transverse septum. 
(V) The slieath of an Oscillaria and Lyngbya are two enti- 
rely different structures, the former as just stated being the 
coherent cell-sheath, whilst the latter is liomologons with the 
external mucilage of Anabaena etc, Within this latter slieath 
the filaments of Lyngbya present a strnctnre, identical with that 
of Oscillaria. 
(VI) In Tolypothrix and Bivularia on the other hand the 
actual filament (within the external slieath) is provided with a 
cell-sheath, which is only in part coherent and shows a very 
marked moniliform strnctnre. 
(VII) The intercellülar protoplasmic Connections of many 
ob Servers 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 throngh the cell-membrane. 
University College London 
September 20 th , 1904. 
ßeferences to Literature. 
Bornet et Flahanlt: Revision des Vostocacees lieterocystees etc. (Ami. 
Sei. Hat. Ser. VII. T. III. etc. 1886.) 
Borzi: Vote alla morfologia e biologia delle Alglie ficocliromacee. (Xnovo 
giorn. botan. ital. Vol. 10. 1878. p. 236). 
Borzi: Le comunicazioni intracellulari delle Nostocliinee. (Malpighia. Ami. 
I. 1886. p. 74 et seq.) 
Brand: Der Formenkreis von G loeocapsa alpina Nag. (Botanisclies Centralbl. 
Bd. LXXXIII. 1900.) 
Brand: AlorptiologiscL - physiologisclie Betrachtungen über Cyanophyceen. 
(Beihefte z. Botan. Centralbl. Bd. XV. 1903. Heft 1.). 
Brand: Über das osmotische Verhalten der Cyanopliyceenzelle. (Ber. 
Deut..Bot. Ges. Bd. XXI. 1903. Heft 6. p. 302.) 
Correns: Über die Membran und die Bewegung der Oscillarien. (Ber. 
Deut. Bot. Ges. Bd. XV. 1897. p. 139). 
Dangeard: L’Iutophagie sexuelle. (Le Botaniste. Ser. VI. 1899.) 
Fritsch: Studies on Cyanopliyceae. I. Some points in the structrure of an 
Anabaena. (The blew Phytologist. Vol. III. 1904 Xr. 4.).. 
