574 DESCKIPTION oi- \_Polygastrica. 



withdrawn. Foimd in summer in muddy water. Size I -140th to 

 l-108th. 



BuESAEiA entozoon. — Body large, cylindrical, turgid, nearly equally 

 rounded at the extremities ; mouth small, situated near the frontal 

 apex. Pound, with the following, in the rectum of Hana temporana 

 (the Frog), in summer and winter. 



B. intesti7ialis ( Vibrio vermiculus, M.) — Body slender, cylindrical, 

 attenuated posteriorly ; mouth small, below the frontal apex. In this 

 species, as well as in others, Ehrenberg has seen transverse self- 

 division. Size l-240th to l-120th. 



B. (?) cordifonnis. — ^Body reniform, front depressed, mouth slightly 

 curved in a spiral manner; colour white. Size 1-2 10th. 



B. lateritia {Trichoda ignita, M.) Tlie hricJc-red coloured Bursaria. 

 — Body compressed, ovato-triangular, with the front sharply crested. 

 Found with Lemna, Conferva, &c. Size 1-43 0th to 1-1 44th. 



{h.) Feontoijia. — Anterior part of the body {brow) projects beyond 

 the mouth, and is convex. 



B. vernalis {Leucopihra virescens, M.) — Body oval, tiu'gid, rounded 

 at the ends, and attenuated posteriorly. The mouth has a wreath 

 of stiff short bristles, resembling teeth ; numerous stomach vesicles 

 are often filled with large Oscillatorise, Naviculse, &c., and contain a 

 reddish bile. The process of digesting the Oscillatorise is interest- 

 ing to follow : — they are at fii'st elastic and rigid, and of a beautiful 

 blue green colour, then distinctly lax, flexible, and bright green, 

 becoming afterwards yellowish-green, and falling into separate 

 articulations, which at length turn yellow. Found amongst Oscil- 

 latoria in spring. Length l-144th to 1- 120th. 



B. leucos. — Body oblong, cylindrical extremities nearly equi-con- 

 vex, bile colourless (see f. 295). This creature has a contractile 

 bladder, with a curious jagged margin near the long open mouth. 

 Found with Oscillatoria, and on the surface of water. Size 1- 144th. 



B. pupa. — Body white, ovato-oblong, rather acute posteriorly; 

 mouth aperture inferior, and near the frontal apex (see f. 296). 

 Found in chalybeate water in Germany. Size 1 -280th. 



B. Jlava. — Body ovato-oblong, often acute at the posterior ex- 

 tremity ; the mouth appears as a flat cavity immediately behind the 

 round brow. Found in bos Avatcr. Size 1-1 40th to l-96th. 



