264 



FRESH-WATER BIOLOGY 



162 (159) Lorica with a pedicel Derepyxis 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 AC Attached to algae. 



FIG. 437. Derepyxis amorpha. X 1000. (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 fj.. 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 ot lorica 15 /*. Pond water. 



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



