A PIECE OF WEED AND SOMETHING ON IT. 3 
A PIECE OF WEED AND SOMETHING ON IT. 
Plate L. 
T any season of the year the working microscopist is seldom at 
a loss to find suitable hunting ground; but perhaps of all 
places more frequently visited than others, are the banks of ditches 
and ponds, and wet or boggy tracts of country. 
Let us betake ourselves to the ditch side, and there, no doubt, 
we shall find a plentiful supply of a rather common weed, the 
Myriophyllum spicatum. ‘This weed, or rather aquatic herb, be- 
longs to the natural order Haloragez: it is a member of the 
Mare’s-tail family. 
The student may think, perhaps, that because the weed isa 
common one it should be passed by, as affording nothing for ob- 
servation of interest; but such notions must not be tolerated for 
a moment when dealing with such widely-spread organisms as In- 
fusoria, for all weeds, however common, are generally found 
encrusted with many different and often rare species. Azacharts 
alsinastrum is a still more abundant weed than the AZyriophyllum, 
and this we have often found with a host of organised appendages, 
Acineta, Vaginicola, Vorticelle, Cristatella, and others. 
But to return to the Myriophyllum spicatum—Mr. Bolton sent 
us a few weeks ago a piece of this weed encrusted with many 
different species of Infusoria, besides which were many species of 
Desmids and Diatoms with various filamentous confervoid alge, 
which entangled the former in their convolutions. The Desmid 
Pediastrum granulatum appeared remarkably perfect when, after a 
little difficulty, we managed to isolate it from its surroundings. 
The more interesting organisms, however, were the genera of 
Mr. Saville Kent’s newly established order of the Choano-Flagellata 
represented by the species Codosiga botrytis and Salpingeca ampho- 
vidium. Mr. Saville Kent has sent us the drawing which forms 
Plate I., and which was executed from a piece of AZpriophyllum 
derived from a similar source. 
The largest central figure is a representation of Vaginicola val- 
vata, a species of the family Vorticellidz of the class Ciliata: the 
body is sessile, and is contained in a sessile urceolate membranous 
sheath, furnished internally with a valve-like operculum which 
closes down and protects the animalcules from molestation when 
in their contracted state, as indicated in the figure. At A is to be 
seen Codosiga botrytts under an amplification of about 700 diame- 
ters—that is to say, in order to arrive at the same magnification 
the observer must use his quarter-inch objective with the D eye- 
