400 OHIO BIOLOGICAL SURVEY 



tinct neck; interior cell oval, nearly or quite filling protective 

 envelope; chloroleucites large, discoid, without pyrenoids; fla- 

 gellum( ?). 



L. 18/x. D. 14/.. 



Distribution, Hungary (Balaton). Found on Tribonema. 



7. Gen. COLACIUM Stein. 



Species attached by a pedicle to Cyclops and other small Crus- 

 tacea as a rule during later stages, free swimming during early 

 stages of development. Form oval or cylindrical, several indi- 

 viduals usually being united into a colony attached by a single 

 stalk ; structure similar to Euglena, the flagellum becoming lost 

 as the forms become sedentary. 



Distribution, cosmopolitan. 



TABLE OF SPECIES. 



A^ Body oval. 



B' Basal stalk shorter than length of individual. 1. C. vesiculosum Eh. 



B- Basal stalk much longer than length of indi- 

 vidual. . . > . . . 2. C. arbuscula 

 A- Body cylindrical . . . . . . 3. C. calvum 



='=1. C. vesiculosum Ehrenberg (Fig. 13, PI. XXI). 



Form oval with basal stalk shorter than length of individual ; 

 length about two and one-half times the diameter when extended 

 tapering toward each extremity but more attenuate posteriorly, 

 pyriform and widest anteriorly when contracted ; motile individ- 

 uals resembling Euglena; chloroleucites oval, numerous; colonies 

 consist of from two to eight individuals. 



L. 19-2V D. 9-17/x. 



Distribution, cosmopolitan. Found on Cyclops, Copepods, 

 Rotifers, etc. 



Variety Platans I^emm. forms free swimming colonies of 4 

 transversely arranged cells. 



A colony consisting of two representatives was found in a 

 culture March 26, 1912, obtained about two weeks earlier from Mir- 

 ror Lake on the campus of the State University at Columbus. 

 These were attached to the second right swimming appendage of 

 Cyclops sp. (Nauplius stage) . A camera lucida drawing was made 

 and while they were being studied a predatory Coleps hirtus hap- 

 pened along devouring both individuals. , 



