point), lateral margins undulate, diverging, gradually enlarging at 

 first and then slightly flaring to a wide mouth; loricas 6.5-8.6/a in 

 diameter, 45-100/x long. 



Common in the euplankton of a variety of lakes; mostly in hard 

 or semi-hard water. Mich., Wis. 



Dinobryon calciformis Bachmann 1908, p. 82 

 PI. 98, Figs. 8, 9 

 Loricas elongate-conical, solitary, epiphytic in the mucilage of 

 Coelosphaerium, Microcystis, and other colonial Cyanophyta, nar- 

 rowed posteriorly to a sharp point; lateral margins smooth, shghtly 

 convex or diverging symmetrically, then converging to a wide mouth; 

 5-6/A in diameter, 30-40/x long. 



Attached in the mucilage of colonial blue-green algae in plankton 

 of many lakes and ponds. Mich., Wis. 



Dinobryon cylindricum Imhof 1883 ex Ahlstrom 1937, p. 148 



PI. 107, Fig. 1 



Loricas closely arranged in divergent but compact colonies, 

 with flaring (sometimes almost campanulate) mouths, irregularly 

 or unsymmetrically tapering posteriorly to a blunt or relatively 

 sharply pointed cone, decidedly and suddenly swollen just above 

 the cone-shaped posterior portion, usually more on one side to 

 produce an angular protuberance, the lorica with one or both 

 margins concave above the swelling; loricas 8.5— 12.5/a in diameter 

 at the mouth, 30— 77/i, long. 



Euplankter. Mich., Wis. 



Dinobryon divergens Imhof 1887, p. 134 

 PL 98, Fig. 7 

 United in diverging and much-branched colonies. Loricas densely 

 arranged, cone-shaped, the posterior portion bent at an angle of as 

 much as 90 degrees from the longitudinal axis and blunt-pointed, 

 the lateral margins irregularly undulate, slightly diverging anteriorly 

 to form a campanulate mouth; 7-8/^ in diameter, 35-50/^ long. 

 Euplankter; common in many lakes. Mich., Wis. 



Dinobryon sertularia Ehrenberg 1835, p. 280 

 PI. 98, Fig. 10 

 Colonies slightly diverging. Loricas fusiform-campanulate; pos- 

 terior blunt-pointed; lateral margins smooth, convex, narrowed above 

 the midregion and then slightly flaring to a wide mouth; 10-14/x in 

 diameter, 30-40/a long. 



[378] 



