152 ELECTRON-MICROSCOPIC STRUCTURE OF PROTOZOA 



(Fig. 61, PL XVI), The attachment organelle is a cigar-shaped 

 projection, with a membrane underlain by spirally twisted fibrils 

 enclosing .1 granular cytoplasm. At its base is .1 row of dense, 



fibrous structures known as the basal plaque, and, below this, a 

 root thai is indistinguishable in structure from the axostyle. The 

 position of this root relative to other anterior organelles is riot 

 described. 



One ot" the more remarkable features of Pj is its 



apparent lack of any parabasal apparatus. No structure resembling 

 a Golgi element was encountered by Grass6, who is a past master 

 at discovering Golgi bodies. Other pvrsonvmphids are believed 

 to possess them, but members of one related order apparently do 

 not. Grasse* also was unable to find any organelles identifiable as 

 mitochondria in Pyrsonymp 



In a complex mctamonad, Joema, mentioned briefly by Grasse 

 (1956b), a striated axial ribbon connects the centrosome to the 

 noncontractile axostyle, which is formed of concentric Livers of 

 fibrils (Fig. 58, PI. W ^ rather resembling those in the axostvle 

 wall in Tritric as and in Foasna. Grasse* states that an axial 



ribbon exists in trichomonads he has examined, and believes that 

 all of these axostvlar connectives are homologous ccntrosomal 

 derivatives, about which the inert or contractile fibrils of the 

 axostvle differentiate secondarily. He does riot comment on the 

 resemblance of the axial ribbon to the rhizoplasts ot some phvto- 

 tlagellates And to the parabasal filament in trichomonads. 



Among the higher metamonads (hypermastigotes) that are 

 thought to be derived from trichomonads, genera representing 

 three different orders have been examined with the electron micro- 

 scope. Beams, King, Tahmisian, and Devine (1960) have studied 

 Ljopbomonas striata (Order Lophomonadida) from the cockroach 

 gut, and Beams, Tahmisian, Anderson, and Wright (1961) report 

 owl., blattan w. Pitelkaand Schooley(1958) and Grimstone (1959a, 

 1959c, 1961) have examined species of Trk a (Order 



Trichonymphida) from termites, and Gibbons and Grimstone 

 (1960) have reported on details of flagellar structure in Tricbottympba, 

 (Order Trichonymphida) and Ho/omastigptoides 

 (Order Spirotrichonymphida of Grasse") from termites or the 

 woodroach. All of these organisms are uninucleate but bear 



