GENUS BLEPHARISMA. 585 



The rounded contour of this species, as first figured and described by 

 Wrzesniowski,* at once distinguishes it from the previously enumerated salt-water 

 representative of the genus. The author has recently received examples of this 

 animalcule from the neighbourhood of Birmingham through Mr. Thomas Bolton. 



Genus II. BLEPHARISMA, Party. 



Animalcules free-swimming, persistent in form, the anterior region 

 much compressed, pointed, sickle-shaped, and curved towards the left ; 

 peristome-field consisting of a long, deep, fissure-like cleft situated on the 

 left-hand border of the body, extending to the median line of this border 

 and continued inwards as a short funicular pharynx ; the outer or left-hand 

 margin of the peristome only bearing the larger adoral cilia, a short undulat- 

 ing membrane protrusible from the basal portion of the right-hand margin ; 

 endoplast ovate or elongate ; contractile vesicle single, subterminal ; anal 

 aperture postero - terminal. Inhabiting fresh water, usually brightly 

 coloured. 



The two types Blepharisma hyaUniim and B. persicinum referred to this genus as 

 instituted by Perty, are identified by Stein as varieties only of the same form and 

 equivalent to the Biirsaria lateritia and Loxodes cithara of Ehrenberg, these corre- 

 sponding again with the Plagiotoma lateritia of Claparede and Lachmann. From 

 Plagiotoma the representatives of this genus are to be distinguished by the presence 

 of the delicate undulating membrane and by the slightly spiral instead of perfectly 

 straight disposition of the peristomal cilia. 



Blepharisma lateritia, Ehr. sp. 



Body lanceolate or almond-shaped, three or four times as long as broad ; 

 peristome reaching to the centre of the median line or sometimes beyond 

 it, the undulating membrane in profile presenting a bristle-like aspect ; 

 endoplast oval, situated in the anterior half of the body; colour peach- 

 bloom, purple-red, or brick-red, rarely transparent. Length 1-456" to 

 1-120". Hab. — Fresh water. 



Although individually persistent in form, the animalcules of this species vary con- 

 siderably in contour among themselves according to their age and stage of develop- 

 ment. Thus while the lancet-shaped contour with sharply-pointed extremities 

 represents the most normal and constant shape, it not unfrequently happens that 

 examples occur in which these terminations are nearly equally rounded, the animal- 

 cules under such conditions closely approaching the form of an almond. The 

 conjugation of two zooids by the application of their oral surfaces, as in Para- 

 m(zcium and other types, was first observed by O. F. Miiller and subsequently seen by 

 Stein. After such conjugation, according to the last-named authority, the endoplast 

 breaks up into from three or four to as many as eight spheroidal fragments, which 

 doubtless represent the germs of new individuals. 



Blepharisma undulans, Stein, Pl. XXIX. Fig. 15. 



Body elongate-lanceolate, four or five times as long as broad ; the 

 peristome extending to one-third only of the length of the whole body ; 

 undulating membrane conspicuous, lamellar, occupying about one-half of 



* " Infusorien aus der Umgebung von Warschau," 'Zeit. Wiss. Zool.,' Bd. xx. 1870. 



