PROCEEDINGS OF SOCIETIES. 59 
common Desmidian, Peniwm digitus, and a number of these 
showed, some individuals one, the majority two, and a few three, 
quite identical stellate bodies in the interior of each cell. These 
were evidently formed at the expense of the cell-contents of the 
individual Penium in which they occurred. Some of these showed 
the cell-contents partially absorbed, and the remainder dead and 
brown ; whilst others did not exhibit a trace of the original con- 
tents, but contained the (generally) two stellate bodies, green and 
vigorous, one in each half of the old cell-wall of the Penium 
which still enveloped them. But afterwards these bodies might 
be found without the encompassing old membrane of the Penium, 
and usually distributed in pairs over the field. 
Now, although in the present instance Mr. Archer was unable to 
trace back these spinous bodies to a Penium, their identity in 
appearance in every way, and the fact of their having been found 
distributed in pairs (as if left behind, as Mr. Archer had seen on 
the previous occasion, by the decayed or dissolved outer wall of 
the Penium), seemed to point out that, be their nature what it 
might, these bodies were in both instances one and the same 
thing, and that in the present instance, like the former, the 
spinous bodies exhibited owed their origin to Peniwm digitus. 
These bodies were, in fact, the “‘asteridia” of the Penium, to 
adopt Thwaites’ term as applied to the stellate bodies occurring 
within the cells of other Conjugate, and, like such similar bodies, 
must probably be regarded as parasitic growths. These, indeed, 
were altogether unlike the smooth, rounded, or irregularly shaped, 
opaque, brownish spore-like bodies, often seen in various Desmi- 
diacez, whose nature continues equally problematical. In the 
present instance, in regard to these bodies, though with green 
cell-contents, like other asteridia, the fact of the cell-contents 
of the original Penium becoming mostly all absorbed—if not 
quite all absorbed, the residue becoming quite effete and brown— 
seems to speak for their parasitic nature. 
But besides the spinous bodies, Mr. Archer likewise drew at- 
tention to anumber of slightly smaller, globular, green and smooth 
cells lying over the field, in some of which a directly transverse 
well-marked light line could be seen, indicating a commencing self- 
division. A few of these bodies might be seen loosely invested 
by a colourless coat, externally covered by slender spines ; these 
loose external coats stood off from the inner spherical, smoothly 
bounded bodies, the whole somewhat like the doubly bounded 
spores of Volvox globator before these assume the golden hue— 
that is, of course, excepting the fact that in the latter the outer 
coat, as is well known, is then destitute of spines. These loose 
outer coats permit the escape of the definitely bounded inner 
smooth cell by the rupture of the former by a large rent. After 
escape this body, in some measure, called to mind, as before men- 
tioned, the still green inner spore of Volvox, or a very small 
specimen of Eremosphera viridis (De Bary), but any one acquainted 
with these forms would at once recognise that it was neither the 
