290 



FAMILY: MONADIDiE 



when spherical, has a diameter of about 4-5 microns. It possesses a 

 spherical nucleus with a large central karyosome. Near the surface of the 

 anterior end of the body is a blepharoplast, from which arises a single 

 flagellum which is as long as, or longer than, the body. Reproduction is 

 by binary fission, and spherical resistant cysts are produced. 



From the intestine of man and animals, several observers have de- 

 scribed flagellates of this type. Liebetanz (1910), who examined the 

 contents of the rumen of cattle, encountered several types of uniflagellate 



organism. A form which had an egg- 

 shaped body and long flagellum spring- 

 ing from its narrow anterior end he 

 placed in Kent's genus Oikomonas, while 

 he created the genus Sph(Eromonas for a 

 type with a spherical body, and the 

 genus Pirotnonas for one with a pear- 

 shaped body and a flagellum arising at 

 a point a short distance behind its 

 narrow anterior end. He further dis- 

 tinguished two species of Oikomonas 

 {0. communis and 0. minifna), three of 

 S-phceromonas {S. communis, S. rninima, 

 and S. maxima), and three oi Pirojnonas 

 {P. communis, P. minima, and P. 

 maxirna). The members of the genus 

 Oikomonas varied in length from 4 to 

 11 microns, those of the genus Sphwro- 

 monas from 3 to 14 microns, and those 

 of the genus Piromonas from 4 to 18 

 microns. It is clearly an error to 

 establish these species on size alone. 

 In fact, Braune (1913) united the 

 species of Sphceromonas in the one 

 species S. cotmnuiiis, while Fonseca 

 (1916) believes that the genus Piromonas is identical with Sphceromonas, 

 and that the difference in the shape of the body described by Liebetanz 

 is only an indication of change in body form. He, nevertheless, records 

 two species of Sphceromonas from cattle which differ from one another only 

 very slightly (Fig. 136). He also records the finding of S. communis in 

 the goat and guinea-pig {Cavia porcelliis), as well as in cattle in Brazil. 

 It is undoubtedly fallacious to separate these uniflagellate organisms 

 in different genera, as Liebetanz has done. It is not improbable that they 

 all belong to the genus Oikomonas. 



1 



Fig. 136. — Sphwromonas communis 

 (1) AND S. liebetansi (2) (x ca. 

 2,000). (Aftek Fonseca, 1916.) 



