264 



FRESH-WATER BIOLOGY 



162(159) Lorica with a pedicel Dere pyxis Stokes. 



Representative species. . . Derepyxis amorpha Stokes 1885. 



Lorica flask-shaped. Pedicel about one-tenth as long as the lorica. 

 Zooid occupying the center of the lorica, subspherical, with the front border 

 pointed. Endoplasm with two greenish-yellow color bands. Length of lorica 

 25 to 30 M- .Attached to algae. 



Fig. 437. Derepyxis amorpha. X looo. ^ After Stokes.) 



163 (158) Forming colonies; loricae beaker-shaped. One primary and one 



secondary flagellum Dinobryon Ehrenberg. 



Representative species. . Dinobryon sertularia Ehrenberg 1838. 



Loricae joined to each other without separate pedicels, 

 the younger individuals being attached by their posterior ends 

 to the inner, anterior edges of the older loricae. Zooids at- 

 tached to the bottoms of the loricae by transparent, elastic 

 ligaments. Chromatophores and eye-spot present. Length 

 of lorica 20 n. Pond water. 



Fig. 438. Dinobryon sertularia. X 750- (After Conn.) 



164 (133) Chromatophores green Order Chloroflagellida . . 165 



165(168) Flagella four; not forming colonies 166 



166 (167) Body enclosed by a lorica Tetraselmis Stokes. 



Representative species. . Tetraselmis limnetis Stokes 1887. 



Lorica broadly oval, zooid nearly filling the lorica, green in color. 

 Flagella exceeding the lorica in length. An amylaceous corpuscle pos- 

 teriorly located. Length of lorica 15 /u. Pond water. 



Fig. 439. Tetraselmis limnetis. X 840. (After Stokes.) 



