’M l C R O S ' C O P l C A*L E SS A Y S , 55'2
129. Cercaria Poduria. Fig. 37 and 38, Plate XXV.
Cercaria cylindracea, poftice acuminata fubfiffa. Cyhndnc
cercaria, the hind-part ftiarp, and fomewhat cloven. '
It r e f em b l e s the young ones of the podura which live among
the lemna is pellucid, and feems to confifl of a head, a trunk,
and a tail • the fore-part refembles the head of a herring, the trunk
Is cylindric, and replete w h i black fp.ral inteftmes; appears
more orlefs ventricofe, at the will o f the animal Nothing tobe
difcovered in the hinder-part. The tail, in molt fituattons, appears
divided into two bridles. When the animal moves, there
Is a continual motion among the inteftmes, which, from the
various fhadesthey occafion, make the body appear very rough ;
fome lateral hairs (cilia) are fometimes perceived. It moves from
one place to another, turning round at the fame time as upon an
axis It is to be found in November and December m marfhy
places that are covered with lemna. Fig. 36, a the head, b the
trunk, c the tail, d with one point, it is feen at e, Fig. 37, wi
two points ; f the hairs on the fide.
130. Cercaria Viridis,
Cercaria cylindracea mutabilis, poftice acuminata fiffa Cylindrical
cercaria, mutable, the lower end {harp, and divided into
two parts.
This animalculum, when in it’s longed {late is not unlike the
preceding; but from the changes to which the body is « B
well as the colour, it differs confiderabiy from it. It fometimes
contrafts the head and tail, fo as to form a fpherical figure : at
others the fides projed outwards. Is found in the fpring, in
ditches o f {landing water.
131. Cercaria Setifera.
Cercaria cylindracea,, ant-ice anguftior, poftice acuminata.
Cylindric cercaria, the fore-part fmalleft, the hind-part pointed.
This is a fmall cercaria, the body rather opake, round, the
upper part bright, and fmaller than the reft; the trunk is
more opake, the tail {harp, near it is a little1 row of {hort hairs.
It has a flow rotatory motion, and is feldom to be met with, and
when found it is in fait water.
132. Cercaria Hirta.
Cercaria cylindrica, antice fubtruncata, poftice obtufa, bimu-
jcronata. Cylindrical cercaria, the fore-part fomewhat truncated,
the-lower part obtufe, finifhlng with two fmall points.
A Cylindrical opake animalculum, with two fmall points at
the lower end, moveable, yet rigid, and placed at fome diftance
from each other; when in motion, the body feems as if it was
furrounded with rows of fmall hairs, feparated a little from each
other. It was obferved in fate water.