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HANDBOOK OF PROTOZOOLOGY 



may occasionally occur in an irregularly diffused or reticulate 

 condition. The number of chromatophores present in an indi- 

 vidual varies in different species. 



In association with the chromatophores are found one or 

 more pyrenoids which are usually embedded in them. A pyre- 

 noid may be naked or covered by amylaceous substance. It 



Fig. 15 a. Trachelomonas hispida from life. X530. (After Doflein). 

 b,c. Propagative cells of Pleodorina illinoisensis. XIOOO. 

 (After Merton). b, from life; c, from stained preparation, 

 d-f. Terminal cells of Hydrurus foetidus, showing the divi- 

 sion of chromatophore and pyrenoid. (After Geitler). 

 g-i. Chlamydomonas sp., showing the division of pyrenoids. 

 (After Geitler). 



multiplies during cell-division. As Geitler showed, the pyrenoid 

 in Euglena and allied forms is naked and may or may not be in 

 the chromatophore; while in Volvocidae or Cryptomonadida it 

 is' encased in a starch envelope. The pyrenoid seems to become 

 the center in the formation of paramylum bodies and allied re- 

 serve food materials. 



