250 Zoology of Colorado 



MASTIGOPHORA (FLAGELLATA) 



These are divided into Phytomastigophora, in which plant 

 characteristics are evident, and in some forms a covering of 

 cellulose is secreted; and the Zoomastigophora, which are more 

 definitely animals. Even in the latter we have such forms as 

 the common Euglena viridis, which is green like a plant. Camp- 

 bell, in his University Text-book of Botany (1907) says of the 

 Flagellata (including Euglena) that they lie on the border be- 

 tween animals and plants, those with green chromatophores 

 being able to assimilate carbon dioxide, like normal plants. As 

 for the Phytomastigophora, including such genera as Peridinium, 

 he boldly classifies them with the plants, remarking that they are 

 excessively abundant in the sea, and are "the original source of 

 food for nearly all marine animal life." It is interesting to think 

 that one can dip a little water out of almost any stagnant pool, 

 and find in it creatures so primitive that they still seem to stand 

 at the crossroads, uncertain whether to enter the zoological or 

 botanical domain. The slime-molds are not intermediate in this 

 sense, for they constitute a specialized group leading to nothing 

 else. Some of the Mastigophora might be thought of as in the 

 line of ancestry of plants or animals, and since evolution has been 

 in progress so many millions of years, we wonder why these 

 primitive beings have remained almost unchanged. It must be 

 because they have lived the simple life, occupying an environment 

 well adapted to their needs, and for which their simple organi- 

 zation is well suited. Under such circumstances, natural selection 

 is a conservative force. 



SPOROZOA 



Parasitic animals, of very diverse kinds. Here falls the 

 genus Plasmodium, the cause of malaria, apparently not native 

 in Colorado. The mosquito Anopheles, which carries the parasite 

 to man, is absent from the greater part of the State, though 

 abundant in portions of New Mexico. In 1922 Dr. Roy P. Forbes 

 of Denver wrote reporting a case of quartan malaria at Denver 

 in a baby seven weeks old. This is due to the sporozoan Plas- 

 modium malar iae of Laveran, which supposedly can only be 

 injected into the body by a mosquito of the genus Anopheles. 

 So far as we have ever been able to ascertain, there is no Anopheles 



