52 DAVKNPORT ACADEMY OF SCIENCES. 



This species is not an abundant form in this state. It has fre- 

 quently been found in pond water in Johnson county, but appar- 

 ently is not of wide distribution. 



Chi^amydomonas sp. 



lyorica transparent, elongate-oval, rounded anteriorly, often 

 acutely pointed posteriorly. Body usually green, almost com- 

 pletely filling the lorica. Flagella two in number, of equal length. 

 A contractile vesicle and pigment spot near the base of the fla- 

 gella, nucleus central. 



Length of lorica, 15-20 microns. (Figs. 62-63, PI- IX.) 



This species which I have referred to the genus Chlamydojuonas 

 differs materially from the one previously described both in the 

 shape of the lorica and the comparative size of the body. In 

 some respects it resembles Chlamydomoyias ovaia Dangeard, and 

 may be identical with that species. It was first observed in an 

 infusion of moss in the locality of Iowa City, during May, 1905. 

 At that time the clas.sification was puzzling, possessing as it did 

 the generic characters of Chlamydomonas , but during the two or 

 three weeks it was under my observation, no chlorophyl was pres- 

 ent; the organism was transparent, slightly granular. 



It was my good fortune, however, to find the same species dur- 

 ing the month of July, 1905, in pond water in Appanoose county. 

 The organisms from this locality left no question as to the genus 

 to which they belonged and convinced me that the forms earlier 

 found were in a saprophytic stage. In the same infusion appeared 

 individuals bright green in color with brilliant eye-spots, also 

 perfectly transparent forms with no eye-spots, while others repre- 

 sented intermediate phases between these two extremes. The 

 transition from the saprophytic to the chlorophyl-bearing stage 

 was readily observed. In the immature individuals the lorica is 

 not easily distinguished from the body, which is usually in close 

 contact with its transparent, investing membrane. In mature 

 specimens, however, the lorica extends beyond the posterior 

 region of the body, either with a rounded border or drawn out 

 into an acute point. The lateral and anterior borders of the body 

 may often be drawn away from the lorica, leaving it visible as a 

 delicate line. 



Reproduction usually takes place by means of segmentation of 



