638 



SYSTEMATIC HISTORY OF THE r^FUSOHIA. 



Genus OPHRYOGLENA (XXY. 334, 335).— Ovoid, ciliated, with an eye- 

 speck anteriorly. Locomotion effected by the numerous regular longitudinal 

 rows of cilia. Some of the numerous digestive vacuoles are often filled with 

 Naviculce. The' mouth is situated in a fossa beneath the brow on one side ; 

 and the anal orifice lies upon the dorsal surface, at the base of the little tail. 

 A large central nucleus and one or more contractile vesicles are found ; trans- 

 verse and longitudinal self-division have been observed. A large red or black 

 stigma is always present on the frontal region. These Infusoria are found in 

 stagnant fresh water, but not in infusions. 



As Dujardin rightly remarks, this genus differs from Koljpoda only by 

 having a stigma or eye-speck ; however, he prefers to place it among Bur- 

 sarina, because the mouth is situated at the extremity of a row of cilia. In 

 this transposition of Ojpliryoglena, Perty does not agree, seeing that it has a 

 narrow mouth, and the closest affinity with Panophrys, with which, therefore, 

 he replaces it, along with Paramecium, &c., in the family Paramecina. We 

 are disposed to question its claim to a generic position ; for the coloured speck 

 is worthless as a distinctive character. 



Ophhyoglena atra (Letccopkra Ma- 

 milla, M.). — Blackish, ovoid, compressed, 

 acute posteriorly. A black stigma is 

 situated anterioriy near the dorsal mar- 

 gin. The mouth is at the bottom of a 

 funnel-shaped cavity, commencing im- 

 mediately beneath the brow ; within this 

 cavity Ehrenberg thinks he has lately 

 seen an oval bright gland. The colour- 

 less cilia appear like silver fringe on the 

 dusky animalcule, especiallv those in 

 front. In turf-hollows. 1-180". 



O. acuminata (xxv.334,335). — Brown, 

 ovate, and compressed ; tail short and 

 acute ; stigma red. The brow projects 

 beyond the mouth about the length of 

 the bod}', or, in other words, is situated 

 about the middle. In turf-hollows. 

 1-180". 



O. Jiavicans. — YelloAv, turgid, o\'ate, 

 attenuated and rounded posteriorly; 

 stigma red, irregular in shape ; the cilia 

 near the mouth longer than in the pre- 

 ceding species ; Ehrenberg counted from 

 twelve to sixteen rows at one view. In 

 turf-hollows. 1-144". 



Nothing like a lens can be seen ^^thin 

 the eye-speck ; but close to it there is an 

 hour-glass-shaped body, transparent and 

 apparently structureless. Its position 

 seems fixed, but it may be detached by 

 diffluence of the animalcule,when it swells 

 up in the surrounding water and often ex- 

 hibits a central cavity. Its presence is not 



necessarily associated with the colo^ued 

 stigma : in Ophryogloia atra it is ab- 

 sent ; and whilst Biirsaria possesses this 

 organ, it has no coloured speck. In 

 other Infusoria having stigmata, such as 

 Euglenaea,Peridini£ea, &c., no such organ 

 is discoverable in connexion with them 

 (Miiller's Archiv, 1856, p. 21). Stein 

 advances, as a distinctive character be- 

 tween Oph.Jlavicans and Bursariajlava, 

 the difference subsisting in respect of the 

 nucleolus. 



O. griseovirens (Perty). — Elliptical, 

 with more or less unequal sides ; usually 

 more pointed behind, and romided in 

 front, where a red or dark pigment-speck 

 is visible. Hyaline, and when strongly 

 magnified reticular ; but frequently con- 

 tains grey or gTeen, and in rare cases 

 brown molecules. The marginal cilia 

 very distinct. Oral fossa in anterior 

 half. Movements quick and revolving. 

 1-300" to 1-180".' In ponds, Bern. 



O. Panophrys (Perty). — Large, oval 

 when seen on the wider side ; pointed 

 end posterior ; colour greyish yellow ; 

 without pigment-speck. When seen on 

 the narrow side, the marginal cilia appear 

 in concentric curved lines, whilst on 

 the broad side the cilia are close together 

 and apparently irregular. Movements 

 slow. Usually swims on one of its wider 

 sides, and but seldom revolves. Mouth 

 wide. 1-144". Uncommon. 



Genus DILEPTUS (Duj.) (XXYI. 26).— This genus belongs to the family 

 '' Trichodina " {ante, p. 608), and is thus defined : — Animal with a fusiform 

 body, much elongated anteriorly, like a long neck, with a mouth seated at the 

 base of the prolongation; \dbratile cilia cover the surface, and are of larger 

 size in front and near the mouth. 



Ehrenberg has arranged Dileptus with the Paramecina, although, unlike 



