29S BIOLOGY OF THE PROTOZOA 



the chromatin being in the form of a continuous single looped 

 thread which divides by transverse division (Fig. 57, p. 103. Cf. 

 Fig. 147). 



• 4 



| 



P * 



"'% 



V 



# 



Fig. 148. — Didinium nasulum, section of conjugating individuals. Second meiotic 

 division of the nuclei (P). (Original.) 



In more favorable types of ciliates than Paramecium the number 

 of chromosomes has been made out with some degree of accuracy. 

 Prandtl (1906) found 16 in Didinium nasutum (Fig. 14S). Prowazek 

 (1899) was a little in doubt whether there were 12 or 13 in the 

 nuclei of Bursaria truncatella (Poljansky, 192S, enumerates more 



