254 BUKSARIE^ — BALA.NTIWUM. 



slit-like mouth, I am inclined to think that this species is simply 

 the very common Glaucoma scintillans, Ehrbg. 



Family bursariEvE. 



Heterotrichous Infusoria, with a sometimes oblique, sometimes straight, 

 peristomial cleft, luhich runs from the anterior end of the egg-shaped 

 body, generally on the right side of the ventral surface, as far as the 

 mouth, and is bordered only on the left side by the adoral cilia. 



Balantidium, Clapar^de and Lachma.nn. 



The body is egg-shaped, or rather longer, with ventral and dorsal 

 surface almost equally arched, anteriorly somewhat truncated, and pro- 

 vided with a peristomial region, which narrows posteriorly, and only 

 deviates slightly towards the right side of the ventral middle line. This 

 asymmetrical condition is most striking in a state of rest, when the 

 peristome is bent together into a trough-like shape. The adoral cilia of 

 the left peristomial border differ only slightly in length and strength from 

 the cilia of the body. The mouth occupies the deepest part of the peri- 

 stomial region, and is continued into the interior by a short gullet. The 

 anus at the posterior end of the body is recognisable by the escape of 

 excremeyit. There are generally two or three contractile vesicles. The 

 nucleus is of an oval or short ribbon-like form. All the species live 

 parasitically in the alimentary canal of the Vertebrata, especially in the 

 naked Amphibia. 



The genus Balantidi^im was instituted by Clapar^de and Lach- 

 mann,^ for the reception of Ehrenberg's Bur saria entozoon, hut wa.s 

 erroneously credited with styliform cilia on both borders of the peri- 

 stomial notch. Stein was the first to recognise the true nature of 

 the peristome, and he increased the number of species, partly by new 

 discoveries, and partly by proving that the so-called Paramcecium coli 

 also belonged to this genus. 



Balantidium coli (Malmsten), Stein. 



Malmsteii,'' Archiv. f. patliol. Anat., p. 302, Bd. xii., 1857 (Paramcecium coli). 

 Leuckait, " Parasiten," first German edition, Bd. i., p. 146. 

 Stein, " Organismus der Infusorien," Abth. ii., p. 320. 



Ekeckrantz, Bidrag till kannedomen om de i menniskans tarmkanal fSrekommande 

 Infusorier," Nord. med. Arkiv, No. 20, Bd. i., 1869. 



Wising, " Till kannedomen om Balantidium coli hos manniskan," ibid., Bd. iii.. No. 3, 1871. 



Infusoria with a short oval body (of 0"07 to O'l mm. long by 0"05 to 

 007 mm. broad); the anterior end somewhat truncated, ivith a very short 

 Digitized by Microsoft® 



''^Etudes, loc. eit., t. i., p. 247. 



