It is now considered that _Entamœba undulans_ is a portion of a flagellate, namely, _Trichomonas_.
Doflein gave this name to amœbæ, from 30 µ to 38 µ in diameter, which Kartulis (1893) found on examining the pus of an abscess in the right lower jaw of an Arab, aged 43, and in a portion of bone that had been extracted. The movements of the amœbæ (fig. 11) were more active than those of “dysenteric amœbæ.” Their coarsely granular cytoplasm contained blood and pus corpuscles, and a nucleus was generally only recognizable after staining. Vacuoles were not seen with certainty. Flexner reported upon a similar case, and Kartulis published five additional cases. As in these cases dental caries was present the infection is likely to have proceeded from the oral cavity as a result of the carious teeth. Craig[31] (1911) considers that this parasite is probably identical with _Entamœba histolytica_.
[31] “The Parasitic Amœbæ of Man,” Lippincott, Philadelphia.
[Illustration: FIG. 11.--_Entamœba kartulisi_, Dofl., from the pus of an abscess in the lower jaw, showing different stages of movement. (After Kartulis.)]
In the literature the following species have been reported as occurring in the oral cavity of man:--
_Amœba gingivalis_, Gros, 1849. [? identical with _Entamœba buccalis_.] _Amœba buccalis_, Sternberg, 1862. _Amœba dentalis_, Grassi, 1879.
Far too little, however, is known concerning these to regard them as definite species, that is, independent organisms; Grassi thinks it even possible there may have been a confusion in their case with salivary corpuscles. If they really are amœbæ they are all of them probably identical with _Entamœba buccalis_.
Schaudinn established the genus _Paramœba_ for a marine rhizopod which multiplied by division, became encysted at the end of its vegetative life and then segmented into swarm bodies with two flagella. These multiplied by longitudinal fission, and finally passed into the condition of Amœbæ. Whether the human parasite described by C. F. Craig (1906) as *Paramœba hominis.* belonged to this genus was for a time uncertain. It is now placed in a new genus Craigia, Calkins, 1912, since it possesses only one flagellum.[32]
[32] See Craig (1913), _Amer. Journ. Trop. Dis. and Prevent. Med._, i, p. 351.