PROWAZEKELLA LACERT^E 615 



(Fig. 252). From each of these there passes backwards a rhizoplast 

 (axoneme). The two soon merge into one another, and are continued 

 to the nuclear membrane as a single rhizoplast. In addition to these 

 structures, there are two rings. One surrounds the rhizoplast a short 

 distance behind the basal granules or blepharoplasts, and a kind of funnel 

 connects the ring with the rhizoplast. About half-way between the 

 blepharoplasts and the nucleus is a second ring, which surrounds the 

 rhiziplast. As already described, the spherical nucleus is surrounded by 

 several bodies or a single elongated body which stains deeply. These 

 may be regarded as parabasals. When the flagellate divides there is, first 

 of all, division of the blepharoplasts, and two new flagella are formed. 

 The two pairs of blepharoplasts then s'eparate till they occupy the poles of 

 the elongating nucleus. The chromatin becomes arranged at the equator 

 of an intranuclear spindle in a compact mass formed by a group of 

 chromosomes. The chromatin mass splits into two daughter plates, 

 which pass to the poles of the nucleus which now divides. The parabasal 

 body or bodies become arranged outside the nucleus as an elongate mass 

 parallel to the nuclear spindle, and with nuclear division this divides into 

 two parts. Finally, division of the flagellate takes place. The parabasal 

 bodies persist in the cysts also, and at each division of a nucleus they are 

 divided into two groups, one of which passes to each daughter nucleus. 

 Prowazek (1904a) claimed to have demonstrated a process of autogamy 

 within the cyst, but there is no evidence that such a process takes place. 

 He concluded also that the cysts of the flagellate were identical with 

 Blastocystis. This also is not correct. Typical Blastocystis, which is a 

 vegetable organism, occurs in the intestine of lizards, and is easily mis- 

 taken for the cyst of P. lacertce (Fig. 118). 



Alexeiefl (1911) discovered a form in the intestine of newts, sala- 

 manders, and axolotls. He regarded it as a distinct species, and later 

 (19126) gave it the name P. longifiUs. 



5. Family: EMBADOMONADiD^ Alexeiei!, 1917. 

 The flagellates belonging to this family have ovoid bodies and an 

 anterior nucleus. On one side of the anterior end of the body is a 

 cytostome, and anterior to it, and close to or actually upon the nuclear 

 membrane, are two granules, the blepharoplasts, which give rise to two 

 flagella. One flagellum is long and thin, and passes forwards as an 

 anteriorly directed flagellum. The other flagellum is shorter and thicker, 

 and passes backwards to protrude through the cytostome. There is a 

 single genus which has the characters of the family. 



