OUE FRESH- WATER POLYZOA. 
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are generally covered with scum, and the faded filaments of 
Algae of the same colour as the am’mals. Therefore, if you are 
desirous to learn whether any mill-pool or lake contains Crista- 
tella, the better plan is to search for these round black bodies 
(which Professor Allman has designated Statoblasts ) late in the 
autumn, or in winter, or in early spring, rather than for the 
mature animals. The same advice, too, will be found good in 
the case of other Polyzoa. These statoblasts are always to be 
found, and generally in very great abundance, floating in the 
water, so that all that is necessary is, to dip your collecting 
bottle in, or to skim the surface; the statoblasts are so cha- 
racteristic of the different species to which they belong, that 
you can never doubt what kinds your pond supplies. 
If, however, the fully-developed colony is the object of your 
search — I am speaking of Cristatella, — then in the months of 
June, July, and August you should visit the pond. And here 
let me give a bit of advice : lie flat down (the Cristatellce 
are almost always within a few feet of the bank, covered by 
water varying from an inch in depth to about two feet), and 
with your eyes close to the surface of the water, and with as 
httle disturbance of it as possible, gently clear away the 
floating weeds, and examine the submerged stems of the plants 
in situ, just as they grow in the water ; it is of little use to 
pull the weeds out of the water, and then examine them, 
because it is almost impossible amid the converfoid growth 
which covers the plants to detect the collapsed form of your 
much prized Cristatella, so you must “ stoop to conquer.” 
Probably for a minute or two you will see nothing like the 
object of your search; but be patient, continue to gaze, and 
you will most likely be rewarded by observing, amid the scum 
and confervas, an oblong-shaped feathery object, about one 
inch or more in length perhaps, of a pale yellow colour, bearing 
some resemblance to the well-known gelatinous egg nida- 
mentum of Limneus stagnalis. This is Cristatella Mucedo, the 
queen of Polyzoa ; and if you are not gratified at the sight of 
her extreme beauty, as you gently place her with the weed to 
which she is attached in your collecting bottle, and if you have 
not an intellectual treat over your microscope when you get 
home, it is clear you are no judge of beauty. 
The attached forms of the Fresh- water Polyzoa are not nearly 
so difficult to find ; at least, I speak of those species with which I 
am familiar — such as Alcyonella fungosa, very readily found and 
common everywhere, three or four kinds of Plurnatella, and Fre- 
dericella Sultana. This last-named species appears to be a singular 
exception, in one respect, to the rest ; for while they seem to 
be strictly annual in their duration of existence, Fredericella is 
perennial. At any rate, I have discovered it in mid-winter, 
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