VOLVOCINES, qW 
able, a single colony may on the second day develop 16, on the third 
256, on the fourth 4,096, and at the end of the week 268,435,456 other 
organisms like itself. 
It has been supposed that some of the cells become detached from the 
mature coonobium and pass into a resting condition, but this hasnot been 
positively demonstrated, so that fissuration is the only mode of repro- 
duction at present known. 
A fuller abstract of this paper by Cohn (from “ Nova Acta,” Vol. 
XXIYV., p. 169) is given in Pritchard’s Infusoria (p. 158). 
Plate XXVII. fig. 1. Goniwm pectorale—a, b, c, families in different 
Positions X 400; d, e, the same, rather more highly magnified; f, family 
before division; g, family of 16 cells divided into 16 daughter families; 
a to gafter Stein. 
Genus 43. STEPHANOSPHZERA. Cohn. (1852.) 
Cenobium throughout its whole life rotating and moving, 
composed of 8 green cells, bearing two vibratile cilia, disposed 
at equal distances around a circle, enclosed in a common 
colourless hyaline, globose vesicle. 
Propagation, both by macrogonidia arising from the eight- 
fold division of the green cells, bearing two cilia, with a lateral 
red spot, congregated in families of eight ; and by microgonidia, 
very much smaller, produced by multiplied division, at first re- 
volving within the common vesicle by the action of four cilia, 
afterwards free, escaping singly. 
Stephanosphera pluvialis. Cohn Hedwigia 1, p. 11. 
Cells globose, elliptic or fusiform, often at each extremity 
spreading out in mucous rays. 
Size. Ccenobium :026-052 mm. Cells -006-:012 mm. 
diam. ' : 
Rabh, Alg. Eur. iii. 100. Currey in Micr. Journ., 1858, vi. 
p. 181, t. 6, f. 1-27. Cohn Zeitschr. fur Wiss. Zool., 1852, 
iv.p. 77. Archer Micr. Journ., 1865, p.116. Pritchard Inf, 
p. 529, t. 19, f. 38-58. 
In hollows of rocks, and in pools after rain. 
Stephanosphera was first observed in 1850 in Germany, and since in 
many places, including the British Isles. 
It consists of a hyaline globe, containing eight green primordial cells, 
arranged in a circle in its equator. The globe rotates upon an axis per- 
pendicular to the plane in which the primordial cells are arranged, and 
moves actively in space by the aid of cilia, two of which proceed from 
each of the primordial cells, and pierce the hyaline envelope. The 
primordial cells divide first into two, then four, and lastly into eight 
portions ; these portions separate from each other in a tangential direo- 
tion, thus forming a dise round which a cellular membrane is developed. 
Two cilia are produced upon each segment, and thus eventually eight 
young individuals are formed, which ultimately escape by fissure of the 
