4 TUFTS COLLEGE STUDIES, VOL. IV, No. 7 



CHARACIOPSIS Borzi, 1894, p. 151. 



Cells lanceolate, cylindrical, pyriform or ovoid, solitary or 

 gregarious, attached to plants or crustaceans by a stipe, usually 

 with basal disk ; chromatophores one to several, parietal, disk- 

 shape ; asexual reproduction by uniciliate zoospores with lateral 

 stigma ; in one species macro- and microzoospores ; also by 

 aplanospores ; sexual reproduction by zoogonidia formed 1-4 in 

 an aplanospore, the zygote developing 1-2 zoospores. 



In habit the species of this genus closely resemble species of 

 CHARACIUM, but possess asexual reproduction, have zoospores 

 with only one cilium or with merely the rudiment of a second 

 cilium, and have no pyreuoid. Lemmermann, 1914, is a mono- 

 graph of the genus, and is here followed. 



KEY TO THE SPECIES OK CHARACIOPSIS. 



I. Cell with obtuse apex. 2. 



i. Cell with acute or subulate apex. 6. 



2. Mature cell of uniform diam. most of its length. 5. C, cylindrica. 



2. Mature cell of various shape, not cylindrical. 3. 



3. Cell ovoid or ellipsoid, subequally rounded above and below. 4. 

 3. Cell rounded above, tapering below. 5. 



4. Stipe slender, with basal disk. i. (. Naegelii. 



4. Stipe stout, without basal disk. 2. C. tltipsoidta. 



5. Epiphytic, 15-25 M long. 3. C. Pyrifonnis. 



5. Epizoic, 50-150 M long. 4. C. grocnlandica. 



6. Cell more or less falcate. 8. C. subu/aia. 



6. Cell not falcate. 7. 



7. Stipe half to twice as long as cell. 9. C. longipei. 



7. Stipe less than half as long as cell. 8. 



8. Cell short-acuminate, straight at both ends. 6. C. acuta. 



8. Cell long-acuminate at both ends, more or less oblique. 



7. C. miHHla. 



1. C. NABGBLII (A. Br.) Lemmermann, 1914, p. 253, ti^s. 

 io, 14; Charadum Nafgelii A. Braun in Nageli, 1849, p. 87, 

 PI. Ill, D, a-ra ; Collins, 1909, p. 150; Phyk. Univ., No. 492. 

 Cells ovoid or ellipsoid, broadly rounded at each end, 20-42 X 

 7-18/4, stipe 3-4 n long, with capitate base but no disk ; chro- 

 matophore single; zoospores numerous, escaping laterally. 

 Mass., Pa., Neb. Europe. 



2. C. KLLiPSpiDBA G. S. West, 1905, p. 288, PI. CCCCLX 1 V, 

 fig. 8, a-c ; Collins, 1909, p. 100; Lemmermann, 1914, p. 253. 

 Cells narrowly ellipsoid, obtusely rounded at each end, 15-22 X 

 8-10/4; stipe very short and straight, not capitate; chromato- 

 phores 2-4. Barbados. 



