640 



SYSTEMATIC KTSTOEY OF THE IT^FUSOEIA. 



berg, excejDt in CeratkUum.) A curTcd line of strong cilia leads towards the 

 mouth, which is situated about the median line at the posterior third of the 

 body, and opens into a ciliated oesophagus. The anus is behind the mouth, 

 on the same ventral surface, near its margin. Complete transverse and longi- 

 tudinal self-division is observed. The process of encysting may be presumed 

 general ; in Urostyla Cohn has seen the ulterior development of a cihated 

 embrvo. 



CiHa and ^etx, no styles or uncini 



Brow without horns Oxytricha. 



Brow with horns Ceratidium. 



( With uncini, no styles Kerona. 



Styles, or uncini, or both. \ With styles, no uncini Urostyla. 



\ With styles and uncini Stylonycliia. 



This family is generally similar to the Keronina of Dujardin, — a family 

 of animalcules, according to this observer, much lower in the scale than 

 many in the families previously described, such as Koljpoda, Paramecium, 

 Coleps, &c. 



" Processes in the form of styles or hooks characterize both the ' Keroniens ' 

 and the 'Ploesconiens ; ' but the latter have a shield (lorica), whilst the former 

 are soft and have no sign of an integument. Of the ' Keroniens ' the O.vy- 

 tricha have neither horns nor hooks, but only cirrhi or straight processes, 

 apparently rigid ; another genus, * Halteria,' has large cirrhi like the pre- 

 ceding, but differs considerably in its mode of life and its movements. 



" The Urostyla of Ehrenberg, with styles only, and no hooks (uncini), we 

 unite with Oxijtriclia; and his Stylonycliia, provided with both styles and 

 hooks, with Kerona ; another genus described imder the name of CeratkUum, 

 horned anteriorly, but wanting both styles and hooks, seems to be only altered 

 or mutilated Keronce. On the other hand, Halterkt appears to be included 

 by Ehrenberg among true Urceolaria, in his genus Trkliodina, although it 

 possesses none of the characters. The Keroniens are found in stagnant water, 

 fresh and salt." Perty has established a family Ox\'trichina, which, besides 

 containing two new genera, styled Mitophora and Stichotricha, excludes Cera- 

 tidium and Stylonycliia, referring the species of the latter genus to Kerona. 

 After these exclusions and additions, Perty's Oxytrichina include Oxytricha, 

 Urostyla, Kerona, Mitophora, and Sticliotriclia. 



Genus OXYTRICHA (XXV. 336, 337; XXIX. 21-24).— Styles, uncmi, 

 and horns wanting. The body is soft, flexible, oval or oblong, more or less 

 flattened, and pro\ided with cilia and setae. Their movements are forwards 

 and backwards, often by imi^ulse, — creeping, swimming, and climbing. In 

 all the species, digestive vacuoles are evident ; in five, (ova-like) granules ; in 

 four, a nucleus ; and in five, round contractile vesicles. Transverse and longi- 

 tudinal division is observed in 0. Lepus and 0. Pellionella ; longitudinal only 

 in 0. Cicada, and perhaps in 0. Pidlaster. The Triclioda Nasamomum and 

 T.^tliiopica (Ehr.) and Urostyla belong, in Dujardin's ojoinion, to 0.vytri<:lia, 

 and Oxytricha Cicada (Eh]\) to the Phesconiens. 



WTiilst admitting a genus Oxytricha, Perty makes two divisions of it, the 

 one corresponding generally to Uroleptus (Ehr.), and the second to Oxytricha 

 (Ehr.). The differential characters given are: — a. Elongated posteriorly, 

 embracing most Urolepti (Ehr.) ; h. Rounded posteriorly, equivalent to Oxy- 

 tricha (Ehr.). Under the first division the species enumerated are 0. caudata, 

 0. Piscis, 0. Mnscidus, 0. amhif/na, and 0. Lamella : under the second. 



