184 



PROTOZOA 



Sub Order I. PHYTOFLAGELLATA. Plant-like chlorophyl-bearing 

 flagellates, mostly with eye-specks. VOLVOCINA: Volvox glvbator* green 

 sphere 0.2-0.7 mm - m diameter, consisting of thousands of individuals. ' EUGLE- 

 NID/E: Euglena viridis* (fig. 134), solitary, coloring small pools by their im- 

 mense numbers. CHRYSOMONADINA, plant-like in nourishment- Dinobryon * 

 Sub Order II. CHOANOFLAGELLATA. With collars; mostly small 

 colonial forms. Codosiga* Conocladium (fig. 136). Sub Order III. EUFLA- 

 GELLATA. Animal flagellates, taking solid food by pseudopodia or by cyto- 

 stome. Here belong, besides numerous free forms, several parasites of man: 

 Laniblia intestinalis (fig. 140), also in rats and mice: Trichomonas hominis in- 

 small intestine. T. batrachomm (fig. 141) is similar. Numerous flagellates are 

 blood parasites, among them Trypanosoma brucei, which is introduced into 

 horses and cattle in Africa by the tze-tze fly (Gloss ina morsitans), sometimes deci- 

 mating the herds. Two other species, Tr. evansii and Tr. cquiperdum attack 

 horses. Tr. gambiense (castellan i) occurs in the blood and cerebrospinal fluid of 

 man in tropical Africa, causing the 'sleeping sickness,' especially fatal to negroes, 

 intermediate host Glossina palpalis. Tr. Icu'isii (fig. 138) in rat's blood. 



Since the reproductive stages of Tr. ziemanni show many resemblances to 

 iheSpiroc/ia-to', the latter, long regarded as Bacteria, may be flagellates. These 



extremely dangerous organisms multiply by longi- 

 tudinal division (the Bacteria by transverse), have 

 a very motile corkscrew body, prolonged at either 

 end into a flagellum. Sp. pallida (fig. 142) cause 

 of syphilis; Sp. recurrent, introduced by blood 

 sucking arthropods (ticks, lice), causes recurrent 

 typhus. Possibly Licshmania, which causes spleno- 



lf ^jjjj!& r rj^, megaly and the Aleppo evil in man in warm 



,?- "-/ .-'vYV/ -$&< climates, belongs near here. 



Order II. Dinoflagellata (Cilioflagellata). 



These forms, occurring in both fresh water and 

 the sea, are placed near the plants because, with 

 their brown chromatophores, their food relations 

 are like those of plants, although the taking of 

 solid food by a mouth opening has been observed. 

 The armor formed of cellulose plates is also plant- 

 like. This armor is divided by a groove into two 

 parts which recall somewhat a box and its lid. 

 There is also a longitudinal furrow which crosses 

 the other. At the crossing are two flagella; the 

 one in the transverse groove was regarded as a 

 circle of cilia, whence the old name cilioflagellates 

 given the order. Peridinium tabulatum and Cera- 

 tium connttum, fresh water (fig. 143); Ceratium 

 tripos* marine. 



aaJt 



FIG. 143. Ceratium cornu- 

 tum (after Stein), apo, ante- 

 rior horn with opening; aah, 

 rsh, posterior and right horn; 

 g, flagellum; gs, flagellar 

 groove; //, longitudinal 

 groove; r, rhomboidal plate; 

 v, vacuole. 



Order III. Cystoflagellata. 



The cystoflagellates, characterized by a gelatinous body surrounded by a 

 membrane, include three or four species, all marine, which differ markedly in 

 external appearance. Noctiluca milians* (fig. 144), is remarkably phos- 

 phorescent. These spherical forms, about i mm. large, sometimes occur in 

 such numbers at night as to make the sea light at the slightest agitation. 

 The phosphorescence is apparently caused by oxidation processes in the proto- 

 plasm. The body, a gelatinous sphere, is covered by a membrane, interrupted 



