C. M. Wen yon 
. 361 
Multiplication. 
The flagellate multiplies in two ways, either by simple division or cyst 
formation. I have not been able to trace the division in much detail, as 
dividing flagellates were not numerous in my preparations. However, evident 
dividing forms were seen in which two nuclei were present, each with its ble- 
pharoplast and rhizoplast passing into two flagella. The parabasal bodies were 
divided between the two nuclei so that in nuclear division those of the original 
nucleus are evidently divided into two more or less equal groups, as occurs in 
nuclear division within the cyst. 
Encystment takes place in the hinder part of the gut of the lizard and is 
preceded by a change in shape of the organism. It becomes an ovoid body 
and apparently two of these become encysted together (PL XX, Fig. 3, n). 
A feature of the encystment is that clumps occur, the individuals of which 
are all in approximately the same stage of development. The clump appears 
to be held together by an adhesive material in which various bacteria and 
other intestinal debris are included. 
The first stage is the formation of the ovoid body, which loses its flagella. 
Two of these come together and a cyst wall is formed round the pair (Fig. 3, 
j and o). The cyst wall is evidently of a gelatinous nature, for bacteria and 
other debris adhere to it. Within the cyst the two organisms fuse, as noted 
by Prowazek (1904), and this, I believe, is followed by fusion of the nuclei 
(Fig. 3, p-s). I can see no evidence of an autogamy as described by him. 
The next stage is the appearance of a vacuole in the cytoplasm of the 
zygote and this gradually increases in size, evidently by absorption of fluid 
through the cyst wall, till the cyst becomes many times its original bulk. Con¬ 
currently with this vacuolation nuclear division takes place (Fig. 3, t-y). The 
original nucleus of the zygote has the same structure as that of the flagellates, 
being^ spherical with a nuclear membrane and central karyosome (Fig. 3, r 
and s). The parabasal bodies lie around the nucleus. The exact similarity 
between the nuclei of the cyst and the flagellates makes it practically certain 
that they are in reality flagellate cysts, quite apart from the stages of en¬ 
cystment where every step can be followed. In division the karyosome divides 
and the two parts separate, while they remain connected by a fine fibre 
(Fig. 3, u-w). The nuclear membrane elongates at the same time, and finally 
two nuclei are formed by constriction at the middle. The parabasal bodies 
remain at the equator of the elongating nucleus for some time and then they 
are divided into two groups which pass to the daughter nuclei. These bodies 
are of various sizes and they do not appear to form anything in the nature of 
chromosomes. I cannot say if any actual division of each separate mass takes 
place but each of the resulting groups of daughter parabasal bodies contains 
more or less an equal amount of material. The nuclei continue to divide in 
the same manner till as many as 32 are formed within the now very enlarged 
cyst (Fig. 3, m, l, i). The majority of the cysts are spherical but some are 
