618 FAMILY: EMBADOMONADID^ 



in breadth from 3 to 4 microns, while the spherical forms were about 

 9 microns in diameter. The anterior flagellum was as long or longer 

 than the body, while the thicker cytostomal flagellum was shorter than 

 this. Many of the spherical forms were evidently dividing flagellates, as 

 they were seen to possess two cytostomes, one on each side of the anterior 

 end of the body, and two pairs of flagella. 



The encysted forms as seen in fresh material are whitish, opalescent, 

 pear-shaped bodies (Fig. 255, 7-8). The anterior end is distinctly narrowed, 

 and often forms a sort of tubercle. In the living condition they vary in 

 length from 4-5 to 6 or even 7 microns, while the breadth varies from 

 3 to 4-5 microns. Dobell and O'Connor (1921) have given the dimensions 

 of the cysts as less than this, but their measurements were taken from 

 fixed and stained preparations made by the writer and O'Connor in Egypt. 

 The writer has recently examined further fresh material, and can verify 

 the measurements previously given in the account by the writer and 

 O'Connor (1917). In stained films the flagellates are seen to have an 

 alveolar cytoplasm, within which bacteria may occur in food vacuoles 

 (Fig. 255, 9-13). Near the anterior end is the spherical nucleus, which 

 has a central karyosome. On the nuclear membrane occur two granules, 

 the blepharoplasts, from which the flagella arise. Several stages in the 

 division process were seen, but the details were not followed. The 

 spherical forms with two cytostomes were seen to have two nuclei and four 

 flagella, while other similar forms were seen with an elongated dividing 

 nucleus with a pair of blepharoplasts and two flagella at each extremity 

 of the nucleus. It is possible that the margins of the cytostome are 

 supported by marginal fibres, as in Chilomastix, but the small size of the 

 organism makes it difficult to determine this point with accuracy. 



In stained films the cysts are seen to have a somewhat peculiar internal 

 structure. There are generally two dark lines marking out an elongate, 

 oval, or spindle-shaped area within the cyst (Fig. 255, 14-19). It is often 

 nearly as long as the cyst itself, and within it is what appears to be the 

 karyosome of the nucleus. In some cysts two dumb-bell-shaped bodies or 

 karyosomes are seen. The writer and O'Connor (1917) interpreted the 

 structure as being a much elongated nucleus. A very similar body was 

 figured by Dobell (1909), and interpreted as the elongated nucleus in cysts 

 which he identified as being the encysted forms of Trichomonas of the frog, 

 but which are probably cysts of a species of Efnbadomonas which the writer 

 has seen in English frogs. Dobell and O'Connor (1921) figure the cyst of 

 E. intestinalis as having a round, more or less central nucleus, and the 

 outline of the cytostome at one side towards the anterior end. Jepps 

 (1923) has figured the cyst as having an elongate central cytostome and a 

 round nucleus with central karyosome (Fig. 255, 25-26). The cyst thus 



