M. R. Leuckart on Paramecium ? c6{\, Malmsten. 437 



no more than two distinct faunas, the more southern including 

 the countries and provinces bordering both sides of the Medi- 

 terranean, the other occupying the temperate regions of Germany, 

 France, Britain, &c., the species diminishing in number as you 

 proceed northward, and only a few extending into the Arctic 

 Zone, from which there appears to be a total absence of any 

 peculiar forms*. 



It only remains for me to say that, although the results of 

 my observations may differ materially from those arrived at by 

 Mr. Jeffreys, I am by no means insensible to the obligations we 

 are under to that gentleman for his valuable researches in the 

 British seas, particularly in their remote northern limits, where 

 dredging is a much more arduous occupation than in more 

 genial cHmes or more sheltered situations. 



XLIII. — On Paramecium? coli, Malmsten. 



By R. LEUCKAETf. 

 [Plate XVIII. figs. 12, 13.] 

 Under the above name Malmsten of Stockholm some time since 

 described an Infusorial animalcule % which occurs in the cajcum 

 and colon of man, but had then only been observed twice, simul- 

 taneously with ulcers in the colon. In both cases it was present 

 in innumerable quantities, and in the fa'st case was to be found 

 even after the healing of the ulcers, during the continuance of 

 lieutery ; so that Malmsten is inclined to think that this latter 

 disease might be referred to the parasitism of our Infusory. 

 The description of the parasite, drawn up by Loven, runs as 

 follows : — 



" The animal is cylindrical, oval, a little pointed anteriorly, 

 broader or narrower according to the quantity of nourishment 

 taken in, and narrower also when it moves through the mucus, 

 turning continually upon its axis. Its length is about 0-1 mill. 

 On the external membrane it has a dense coat of cilia, which 

 stand in somewhat oblique series. In front, on one side of the 

 apex, is the mouth furnished with long cilia ; and the oesojjhagus, 

 which is slightly dilated and somewhat curved, penetrates the 

 interior to a considerable depth. In the interior parenchyma a 

 dark streak sometimes indicates the course of a swallowed moi-sel. 



* Greenland is considered by many naturalists to form part of the same 

 province with Northern Europe, and has a few peculiar land and fresh- 

 water shells ; hut their distinguishing characters are extremely slight. 



t Translated from Wicgmaun's Arehiv, 18G1, p. 81, hv W. S. Dallas, 

 F.L.S. 



X Translated in Virchow's Arehiv fur pathol. Anat. und Physiol. 1857, 

 vol. xii. p. 302, tab. x. 



