STaUCTURE AND LIFE-HISTOllY OF CRITHIDIA MELOPHAGIA. 199 



rod-like, usually lies transversely across the organism (PI. 12, 

 figs. 21-28). It is exceptional to find it in any position other 

 than anterior to the nucleus, though on a few occasions the 

 blepharoplast was at the postei-ior end of the body (PI. 12, 

 figs. 40, ■i'2), but in these cases the flagellum originated in a 

 pre-nuclear position. 



As a rule the blepharoplast shows no differentiation of 

 structure (PI. 12, figs. 21-39), but sometimes in dividing 

 forms, in which the blepharoplast is dumb-bell shaped, there 

 seems to be a concentration of chromatin in the ends of the 

 dumb-bell (PI. 12, figs. 40, 44, 45). A clear area (PI. 12, 

 fig. 31) is often present around the blepharoplast. 



Chromidia are present, scattered in the general proto- 

 plasm (PI. 12, figs. 25, 37, 39). They stain in the same way 

 as the nucleus, and less densely than the blepharoplast. 

 The occurrence of: such chromatoid granules at division 

 (PL 12, fig. 45) suggests that they have been given off from 

 the nucleus into the general protoplasm, and exercise some 

 controlling influence over the same. 



The undulating membrane and the flagellum. — 

 The flagellum originates from a chromatic area in the pre- 

 flagellate form, and is attached to the body by a narrow mem- 

 brane (PI. 12, tigs. 21-46), which is a periplastic outgrowth 

 of the anterior end of the body. There is but one flagellum 

 in any single, undividing individual (PI. 12, figs. 21-39). 

 The flagellum is thick, but gets thinner towards its free end 

 (PI. 12, figs. 40, 45). At times it appears to show very fine 

 transverse striations. 



In stained specimens the membrane sometimes shows myo- 

 nemes (PI. 12, figs. 39, 42, 45), though, curiously enough, the 

 myonemes were much more obvious in some of the living 

 specimens that I examined. Flu described myonemes in 

 C. melophagia, but figured the myonemes as accompanying 

 a central spindle. This latter feature I have never seen. 



A basal granule (blepharoplast of Minchin) is often 

 present (PI. 12, figs. 17, 27, 33, 42, 45) between the point of 

 origin of the flagellum and the blepharoplast (kinetonucleus). 



