366 MR. ALDER ON THREE NEW SPECIES OF ANIMALCULES. 
The body was of a vase or cup form, expanded at the top 
(fig. 1.), and set round with numerous pointed tentacles, abruptly 
thickened towards the base, and forming more than one row: 
they had very little motion, but were occa- 
sionally bent forwards, and the whole were 
sometimes slowly retracted. The body was 
attached to the Sertularia by a tolerably 
stout stem. 
Other specimens of the Sertularia were 
examined and found to have the same 
parasite, which was itself infested by still 
more minute parasitical bodies of the family 
Lacillaria. In addition to the first species 
of supposed zoophyte, another, rather 
smaller, was also detected, (fig. 2). Its body was of an ovate form, 
with a very slender and shortish stem: the tentacles were capitate, 
or knobbed at the end, not so numerous as in the first species, and 
placed in a single row round a narrow disk. Under the impres- 
sion that these animals belonged to the class of zoophytes, I sent 
drawings of them to my friend Dr. Johnston, who informed me 
that they represented something with which he was not acquainted, 
and that possibly I had got a new form of Campanularian zoophyte. 
A more careful examination, however, of these delicate little crea- 
tures, which were so minute as to be only just visible to the naked 
eye, convinced me that their organization was much more simple 
than is to be found in the true polypes, and that they must be 
considered to belong to the class Infusoria. I afterwards found 
both these species on Sertulariz at Cullercoats. 
I have since met with another species of these polype-like 
animalcules inhabiting fresh water, (fig. 3). It occurred in 
Crag Lake, on the stem of the new species of Paludicella found 
there, and somewhat resembles the smaller marine species already 
described, but is perfectly distinct from it as its habitat would lead 
us to expect. The body of this lacustrine species is pear-shaped, 
or, perhaps, rather bell-shaped, with a distinct rim round the top, 
and a single circle of delicate capitate feelers, which, as in the 
former instances, were retractile. The stem was long and slender. 
