RHIZOPODS, ACTINOPODS, SLIME MOLDS, SPOROZOA 91 



tip-to-tip contact of pellicular crests (Fig. 32, PL IX), but Kummel 

 and Klug both reported intimate interdigitation of crests. 



Ectoplasm and endoplasm are more or less clearly distinguished 

 by the absence from the former of inclusions such as granules of 

 stored polysaccharide. Within the low-density ectoplasm beneath 

 the ribbed cortex, a network of fine filaments may appear. Smaller 

 ones, about 5 m/x in diameter, join to produce larger ones that 

 connect with the surface envelope between crests. In addition 

 the Beams group, found in micrographs taken at high magnifica- 

 tion, larger, rather straight tubules that seem to terminate in pores 

 at the cell surface. They suggest that these may be sites of 

 secretion of mucus. Other authors have reported no evidence of 

 pores. Circular myonemes are described by the Beams group and 

 by Kummel as bundles of very fine filaments lying a short distance 

 beneath the cell surface. Their length and relationship with any 

 other organelles are uncertain; whether they could be confused 

 with the possibly filamentous layer underlying the pellicular 

 crests is a moot point. 



A typical feature of these gregarines is a distinct differentiation 

 of the body into two parts, separated by a septum. The nucleus 

 lies in the posterior part. The septum appears to consist of a 

 substantial layer of fine filaments; Grasse and Theodorides suggest 

 that it is continuous with the layer beneath the pellicular crests, 

 but no micrographs showing its peripheral connections have been 

 published. 



Golgi elements are reported by most investigators, but not by 

 the Beams group. Microtubular mitochondria are shown by 

 Kummel in Beloides, and mitochondria of both microtubular and 

 cristal types appear in the micrographs of Stylocephahis (Grasse 

 and Theodorides, 1959), but other workers have not found con- 

 ventional mitochondria. It is possible that species differences are 

 involved; the presence and absence of mitochondria in related 

 species of the malaria parasite have been demonstrated (see below). 

 Discrete arrays of parallel ergastoplasmic membranes are present 

 near the nucleus in Stylocephahis (Grasse and Theodorides, 1958, 

 1959). No evidence of phagocytosis in any of the feeding gre- 

 garines has been reported. The intriguing structure of the 

 nuclear envelope has been described in Chapter 2. 



Early developmental stages of vegetative Gregarina rigida are 



