230 - THE AMERICAN MONTHLY [Aug 
their supply of oxygen and food.? These are en 
which puzzle me.—F’. R. Brokenshire, Exeter. 
[If we understand our correspondent aright, the cell is 
a dry one, and the cover-glass is held in place only by 
the paper covering the slide. The cell would therefore 
not be hermetically sealed. The mite referred to may 
be Tyroglyphus entomophagus or Cheyletus eruditus, the 
book-mite, both of which are not uncommon unfortunately 
in museums and collections, where they feed upon the 
‘specimens, causing much havock. Cheyletus can be dis- 
tinguished by its large raptorial palpi, of which a good 
drawing appeared in Mr. Allen’s “Journal of Microscopy,” 
1893, p. 100. There is a drawing in the ‘“‘Micrographic 
Dictionary,” but it is not accurate.—Science-Gossip. _ 
; Extracts from Postal Microscopical Society’s Note-books. 
Edited for Sctence-Gossip. | 
PARASITE OF GOLD-Fisu.—This is a most voracious 
little creature. As often as I removed him from his host 
he swam directly back again, and it was only with great 
difficulty he could be dislodged. The chief place of at~ 
‘tack seemed to be about the shoulders. At the time I 
caught this parasite I was very much engaged, so I sent 
it to a professional mounter in London to be mounted, 
asking at the same time for any information he could 
give me on the creature. He said he had similar ones 
from the Brighton Aquarium, but could not tell me any- 
thing more. It is a singular creature, possessed of 
numerous ciliated swimmerets; but perhaps its chief 
feature of interest is the means by which it fastened 
itself to its host. These will be seen at the anterior end 
in the shape of two powerful suckers, around which there 
seemed to be a large number of radiating ciliary muscles. 
There are also two singular organs of a triangular shape 
not far from the suckers, apparently of a chitinous sub- 
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