THE EUGLENOIDINA OF OHIO 357 



El Chloroleucites disk form, more or 

 less numerous. 



F^ Form radial not compressed; 

 usually provided with two 



annular paramylon granules. 2. Gen. Leptocinclis 

 F- Form compressed; paramylon 



granules of various shapes. .3. Gen. Phacus 

 E- Chloroleucites in the form of two 



elongate lateral bands . 4. Gen. Cryptoglena 



C- Provided with a brown or brownish-green 

 protective covering which usually bears 



rugosities or spine like processes. . 5. Gen. Trachelomonas 

 B- Typically sessile (free swimming during part of 

 reproductive cycle) and attached to minute 

 Crustacea, rotifers, filamentous algae, etc. 

 Q Not provided with a basal stalk; distinct 



protective envelope present . . 6. Gen. Ascoglena 



C- Provided with a basal stalk; distinct pro- 

 tective envelope not present ... 7. Gen. Colacium 

 A- Provided with two flagella; form bluntly conical with 



posterior end more or less pointed ... 8. Gen. Eutreptia 



1. Gen. EUGLENA Ehrenberg. 



Form oblong or spindle shaped, contractile; free swimming; 

 a single anterior flagellum ; body covered by an elastic periplast 

 often provided with minute elevations arranged spirally; on the 

 anterior end a deep groove from the base of which arises a flagel- 

 lum ; an anterior stigma together with a complicated vacuole sys- 

 tem consisting of a reservoir into which one or more small con- 

 tractile vacuoles open; protoplasm containing green chromato- 

 phores (chloroleucites), together with paramylon bodies both 

 differing greatly in form and position in the various species; 

 nucleus large, centrally located with an interior nucleolar body. 



Reproduction agamous through division occurring either in 

 the free swimming stage, where it is usually longitudinal, or dur- 

 ing an encysted stage, where the single cyst often divides into 

 numerous smaller cysts. Conjugation has not been definitely 

 demonstrated, although a sexual cycle probably occurs. 



The species are found chiefly in stagnant fresh water, although 

 a few are marine and one has been noted as parasitic in a species 

 of Mesostoma, one of the Turbellarians, although not described. 



Distribution, cosmopolitan. 



