PLATE 4 

 Crithidia euryophthalmi from mid-stomach of Euryophthalmus convivus. 



Figs. 40-92. Nectomonads (Figs. 40, 41). Small oval forms at the begin- 

 ning of the developmental series of merozoites or zooids in the early rectal 

 phase, showing nucleus, parabasal body, nuclear rhizoplast, and light area around 

 the parabasal body. Nucleus at posterior end of the body. Anterior end 

 pointed or blunt. 



Figs. 42-47. More advanced stages in the developmental series; width of 

 body and distance between nucleus and parabasal are increasing. 



Figs. 48-54. Size of the oval forms increasing; nucleus still diffuse and 

 located at extreme posterior end of body. Nuclear rhizoplast present, but no 

 indication of the flagellum except in figure 54. 



Figs. 55-58. Developing forms. Anterior end elongating and extending 

 out along the flagellum. Nucleus still diffuse. In figure 58 the posterior end 

 of the body is slightly elongated. 



Fig. 59. A group in upper part of mid-stomach. Note vesicular type of 

 nucleus, with the centriole-like karyosome. Both ends of the body are more 

 or less pointed. The position of the parabasal body near the nucleus is unusual. 



Fig. 60-62. Both anterior and posterior ends are elongating. Vesicular 

 nu'cleus, nuclear rhizoplast, parabasal body, parabasal rhizoplast, and flagellum 

 very distinct. 



Fig. 63. Posterior end blunt; vesicular type of nucleus. Parabasal body 

 near the nucleus. Anterior end of the body well developed; a slight undulating 

 membrane present. 



Fig. 64. Form a little more developed. Posterior end of the body is 

 blunt or round, and nucleus is diffuse. 



Fig. 65. Almost mature flagellate; nucleus diffuse; posterior end elongated 

 and quite broad. 



Fig. 66. Free form, showing vesicular nucleus and a distinct undulating 

 membrane. 



Fig. 67. Nectomonad developing into elongate flagellate; nucleus diffuse. 



Figs. 68-72. Nectomonads of mid-stomach, long, slender, flagellates show- 

 ing the common variations in the nuclear structures. The diffuse type in 

 figure 68; vesicular in figures 69 and 71; chromatin-encrusted nuclear membrane 

 in figures 70 and 72. 



[186] 



