54 Hknfrey, on some Fresh-water Confervoid Algce. 
periphery, so that the frond becomes a hollow body (just as 
the stems of Grasses or Umbelliferce become fistular). The 
walls of the sac then give way, (figs. 29 and 30,) and as the 
expansion proceeds, orifices are formed in diff"erent parts, until 
the whole becomes a coarsely-latticed sac or clumsy net, of 
irregularly-lobed form (fig. 31). Then this becomes broken 
up into irregular fragments (figs. 32 — 34) of all shapes and 
sizes, (giving the stratum a granular appearance to the naked 
eye,) each of which recommences the expanding growth, and 
becomes a latticed frond. The internal cells are very minute, 
but have a distinct margin wdth internal granules (figs. 35 and 
36). They multiply by dividing into two or four. The gela- 
tinous frond always presents a transparent border or peripheral 
stratum, destitute of green cells ; but no boundary membrane 
exists, the surface exhibiting a softened or half-dissolved 
aspect. On the approach of winter the fronds ceased to in- 
crease, and by degrees most of the gelatinous masses faded to 
a light brownish tint, swelled up and settled to the bottom 
of the water in light flocculent clouds. They appear to 
become half dissolved, and to allow the green cells to become 
free, as many of the latter were found free, adhering to the 
sides of the vessel ; perhaps these reproduce the fronds in the 
next season. No zoospores were ever detected. 
The verdigris-like appearance of this Alga when dead is 
most remarkable and characteristic. While growing, in its 
wet state, it is rather of a yellowish opaque green colour. 
As to the systematic position of the above species, Pando- 
rina belongs, of course, to the Volvocinece ; Clatkrocystis is 
doubtless referable to the same group as Palmella cruenta, and 
therefore to the family of true Palmellaeece, which will require 
to be kept apart from Protococcus, and similar forms, on 
account of the absence of zoospores. Apiocystis must remain 
for the present in the heterogeneous assemblage which in- 
cludes Protococcus, GlcBOcapsa, &c., which require much 
more study before they can be satisfactorily classified. 
