328 Illinois State Laboratory of Natural History. 



47. P. californica Shaw ('94). 



Occurred from July to October in both years, often in 

 great abundance, in towings and among vegetation in the 

 river and deeper lakes. 



Family CRYPTOMONADID^. 



Cryptomonas Ehrbg. 



Free-swimming, ovate or elongate, anterior end oblique, 

 with a peristome-like excavation, in wdiich is the oral open- 

 ing, leading to a distinct pharynx ; two llagella issuing from 

 beneath a lip-like anterior marginal prolongation ; two lateral 

 brown to green chromatophores. 



48. C. ovata Ehrbg. 



This was found in both years, but only in September and 

 October. Except a record from substation L it was taken 

 only in the river at E, where it was found excessively abundant 

 in both months. 



Order CHOANOFLAGELLATA. (Collared Monads.) 



Family CRASPEDOMONADIDiE. 



Subfamily CODONOSIGIN^. 



DiPLOSIGA Frenzel. 



Individuals attached singly, without pedicel ; two concen- 

 tric anterior membranous collars, the inner one small, 



49. D. frequentissima Zach. ('94). 



Taken abundantly in April, 1896, and in smaller numbers 

 during the following month in towings from the river chan- 

 nel at E. These minute individuals were attached to the rays 

 of Aster ionella, a colonial diatom. 



ASTROSIGA Kent. 



Individuals united into stellate colonies by the attachment 

 of their pedicels at a common center. 



