THE MAST1GOPHORA 171 



canal opening at the apex of the cell, and one or many accessory 

 .contractile vacuoles discharging into the reservoir (Fig. 5 (17)). A 

 similar kind of compound vacuole-system is also met with among 

 the Peridiniales (Fig. 12). 



The products of metabolism which occur in the Euglenoidea 

 consist of fatty oil and paramylum, a substance allied to starch, but 

 not giving the typical starch-reaction. It is interesting to note that 

 the saprophytic Euglenoids of the tribe Astasiina, which are destitute 

 of chlorophyll, none the less produce paramylum. 



The Euglenoidea include holozoic, holophytic, saprophytic, and 

 mixotrophic species, and one of the most characteristic properties 

 which they have in common is the formation of paramylum as the 

 principal product of metabolism. 



This order presents a series of forms analogous to the Mona- 

 didea in regard to the distribution of the flagella : monomastigote 

 forms (Euglena, Peranema, Astasia) ; paramastigote (Distigma, 

 Sphenomonas, Tropidoscyphus) ; isomastigote (Eutreptia) ; and, finally, 

 he.teromastigote forms (Heteronema, Dinema, Anisonema). 



The Euglenoidea are divisible into two sections and three tribes. 



A. Without special pharyngeal apparatus. 



TRIBE 1. EUGLENINA. 



Holophytic. A red stigma or eye-spot close to the vacuole is present, 

 jand green chromatophores. 



Euglena, Ehrb. (Fig. 5 (13, 17)) ; Colacium, Ehrb. ; Lepocinclis, Perty ; 

 Trachelomonas, Ehrb. ; Eutreptia, Perty ; Ascoglena, Stein ; Cryptoglena, 

 Ehrb. Trachetomonas is sometimes found in the sea ; the others are 

 freshwater forms. 



TRIBE 2. ASTASIINA. 



Saprophytic, without chlorophyll. Astasia. (Fig. 5 (27, 28)), Duj. ; 

 Distigma, Ehrb. ; Sphenomonas, Stein ; Menoidium, Perty ; Rhabdomonas, 

 Fresenius ; Atractonema, Stein. All freshwater forms. 



B. With special pharyngeal apparatus. 



TRIBE 3. PARANEMINA. 



Holozoic. 



a. With one flagellum. Paranema (Fig. 5 (16)), Duj. ; Euglenopsis, 

 Klebs ; Urceolus, Meresch. ; Petalomonas, Stein ; Scytomonas, Stein. All 

 found in fresh water, but Euglenopsis flourishes in vegetable infusions. 

 Copromonas, Dobell (3), parasitic in intestine of frogs. 



/3. With two flagella. Heteronema, Duj. ; freshwater and marine. 

 Dinema, Perty ; stagnant freshwater. Zygoselmis, Duj. ; freshwater. Tropi- 

 doscyphus, Stein ; freshwater; Anisonema, Duj. ; freshwater Entosiphon, 

 Duj. ; marine and freshwater. 



