374 JULIA ELEANOR MOODY 



The sketches of longitudinal sections through the mouth shown 

 in figures 40 and 42, are typical of the structure of this region. 

 I have found no straight rods; in every case the sections show 

 wavy lines, stained somewhat more deeply than the surrounding 

 protoplasm and having the appearance of cortical thickenings. 



A rod-shajoed macronucleus is imbedded in the endoplasm 

 which, in different individuals, shows great variety in form, 

 length and position; sometimes lying fully extended and fol- 

 lowing the circumference of the cell; again straight or loosely 

 coiled in the center of the body; sometimes so tightly twisted 

 as to appear made up of closely united segments (figs. 49, 50, 

 51, 52). In may have been some such closely twisted form as 

 the latter which Entz described as composed of separate spheri- 

 cal segments, appearing like a mass of free nuclei. 



In section the nucleus is seen to be covered with a delicate 

 but distinct membrane, within which, imbedded in an achro- 

 matic substance, lie coarse, deeply staining bodies (figs. 42, 47, 

 53, 65). Scattered throughout the endoplasm are bodies, some- 

 times spherical, sometimes elongated, many of which are solid 

 masses staining evenly throughout, while others show a differ- 

 entiation into several intensely staining granules, surrounded 

 by a pale area of definite outline. In one section a comma- 

 shaped body was found made up of distinct granules which 

 appeared to be in process of division (figs. 47 and 48). Similar 

 bodies are shown in figures 54 and 60, sketches of total mounts. 

 It seems impossible from the present observations to determine 

 the nature of these bodies. Although some of them may be 

 micronuclei, I am inclined to interpret them as nuclei of partly 

 digested Halteria, owing to the fact that there is no constancy 

 in number and that none of them has been observed in process 

 of division. 



4. Reproduction 



Actinobolus radians reproduces by transverse fission, the 

 number of daily divisions showing a wide variation due to the 

 extreme sensitiveness of the organism to food and environmental 

 conditions. During division Actinobolus swims actively about, 



