M i c r o s c o p i c a l E s s a y s . 548
A pellucid cryftalline animalculum, fumiftied with fmaller and
larger fplendid globules fwimming about within it, the under-fide
convex, the upper-fide hollow, the fore-part forming a kind o f
lip.
t 2i. Burlaria Hirundinella. Fig. 19, Plate XXV.
Burfaria utrinque laciniata, extremitatibus produflis.
Burfaria with two little projeSing wings, one on each fide, the*
fore and hind-part produced fo as to give them fome refemblance-
L the head and tail o f a bird. It is mvifible to the naked eye,,
but appears to be a pellucid holloa membrane under the micro-
fcope They have no vifible inteftines ; it moves fomewhat like
a fwallow; a the head, b the tail, c one of the wings.
li22. Burfaria Duplella.. Fig. 18, Plate XXV..
Burfaria elliptica, marginibus inflexis. Elliptic burfaria, with
the edge bent in and out.,
A cryftaliine membrane folded up, no vifible inteftines, if we
except I little congeries of points under one of the folds. Was,
' found among duck-weed.
123. Burfaria Globina.
Burfaria fphaerica, medio pellucentiffima. Spherical burfaria,.
very pellucid in the middle,.
A fubinHW
M i c ro s c o p i c a l E ssays. 549
A fubfpheric hollow animalculum, the lower end furnilhed
with black molecules of various fizes, the fore-part with obfcure
points, the reft entirely empty, and the middle very pellucid;
it moves {lowly from right to left.
XI. C E R c A R I A*.
Vermis inconfpicuus, pellucidus, caudatus. An invifible pellucid
worm with a tail.
124. Cercaria Gyrinus..
Cercaria rotundata, cauda acuminata. This cercana is round,
and has a (harp tail-
The body is white, gelatinous, without any traces o f inteftines;
the fore-part fomewhat globular, the hind-part round, long, and
p o t d f r o « ™ , it appears . iiule » „ p t . i le d on each
The tail is in a continual vibration while it is fw.mmmg, like-
r f Z tadpoles. I. f e » s vety
malcula.
125- Cercaria Gibba.
Cercaria fubovata convexa, antice fubacuta, cauda tereti..
Somewhat o f an oval &ape, convex, the fore-part rather acut ,.
the tail round.
It