248 WILLIAM HATCHETT JACKSON. 
This Infusorian is evidently closely allied to the genus 
Trichodina. The presence of the hooked ring, the striated 
border, the complete circle of motor cilia, at once place it in 
the Peritrichous family—Urceolarina of Stein. All the 
members of this family infest certain animals. TJ. pediculus 
and T. diplodiscus are found on Hydra, the former also in 
the allantoid bladder of Zritons;! T. Steinii, on Planarians (?)?; 
Urceolaria (T.) mitra on Planaria torva, and Trichodinopsis on 
Cyclostoma elegans, and in the pulmonary chamber of the 
same Mollusc®. Whether this animal is or is not restricted 
to Spongilla cannot as present be positively stated. 
The different genera and species of the family Urceolarina 
vary much among themselves. Trichodinopsis and Urceo- 
laria have rings without hooks, but of an apparently twisted 
structure. The former is ciliated all over the body, though 
Stein* states that he found specimens in which this ciliary 
coat was wanting. Trichodina has the ring hooked. 
But our Infusorian in certain points differs fromall the other 
members of this family—(1) in the absence of the adoral spiral 
of cilia, the homologue of the ciliary spiral in the stalked 
Vorticella ; and in the presence of a circle only of motor cilia, 
the homologue of the posterior circle of cilia in the free- 
swimming zooid of Vorticella ; (2) in the presence of the long 
setee (s.) which perhaps point to an affinity with Halteria, as 
mentioned above; (3) in the extreme softness of the body 
and (4) the very peculiar position of the mouth. 
These points seem to me sufficient to warrant the esta- 
blishment of a new genus, to which I should propose to give 
the generic name of Cyclocheia, in allusion to the sete. This 
is a more striking peculiarity than the absence of the adoral 
spiral of cilia—a fact important, however, in the definition of 
the family, which ought to be modified—the two circlesof cilia, 
buccal and motor, being usually present, though the buccal 
spiral is more feebly marked in Trichodinopsis than in 
Trichodina, and in this solitary instance of Cyclocheta has 
become obsolete. 
Appended is the definition of the genus and a table of the 
characteristics of the genera in the family Urceolarina. 
Fam. Urceolarina. Stein. 
Cyclochata. Animal with circle of sete (16 in number) on 
1 Busch, ‘ Miiller’s Archiv,’ 1855, p. 360, Taf. XIV, fig. 2. 
2 Claparéde, loc. cit., vol. i, p. 130. 
3 Clap., vol. i, p. 132. Stein, loc. cit., Abth. I, p. 146. 
4 Stein, loc. cit., Abth. II, p. 146. 7 
