48 COCCOPHYCEJ2. 



Characium Sieboldi. Br. Alg. Urdc. 32 t. 3,/. A. 1-21 . 



Cells erect, equal, at the beginning nearly lanceolate, when 

 older pyriform or obovate, 2-3-4 times longer than broad, apex 

 obtuse or broadly rounded ; stem short, hyaline, base attenu- 

 ated, truncate, not discoid ; contents bright green or yellowish- 

 green, granular, in the beginning with a single amylaceous 

 granule, afterwards with several. 



SIZE. Cells -022--026 mm. diarn. 



Eabh. Alg. iii. 83. 



In clear water, attached to filiform algse. Bangor (W. 

 Joshua) . 



" The gonidia of this species exhibit, after they have already attached 

 themselves by their ciliated extremities, a tremulous motion lasting for 

 almost a quarter of an hour, and evidently commencing in the delicate 

 stalk." Braun p. 230. 



Plate XX. Jiff. 9. Cells in various stages, in situ, X 400 ; 10, cells 

 containing mature zoogonidia ; 11, free zoogonidia. 



Characium omithocephalum. Br. Alg. Unic. p. 42, t. 3 C. 



Cells from the beginning unequal, incurved, distinctly stipi- 

 tate, afterwards one side swollen, semilunate, apex produced 

 into a straight or inclined beak ; stern elongated, slender, base 

 sometimes discoid ; cell-contents bright green, granular, with a 

 central or lateral starch granule. 



SIZE. Cells -025-'U33 mm. long, without stem, half as wide, 

 or more. 



Micr. Journ., 1867, p. 85. Rabh. Alg. iii. 86. 



In pools. 



Plate XIX. fig. 5. a, young cells ; d, cell further advanced ; b, c, f, 

 mature cells in different stages of division ; e, mature cells with en- 

 dochrome artificially contracted, all magnified 600 diameters. 



Characium tenue. Herm. in Rabh. Beitr. p. 26. 



Cells erect, narrowly lanceolate, six times as long as broad, 

 attenuated towards each extremity, somewhat rostrate, and 

 hyaline above ; stem short, slender, not dilated at the base ; 

 contents homogenous, bright green. 



SIZE. Cells -003--006 mm. diam. 



Micr. Journ., 1866, p. 126, 193. 



Characium ambiguum, var. c., Rabh. Alg. iii. 87. 



Attached to filamentous algaa. 

 Plate XIX. Jiff. 4. Cells magnified 400 diameters. 



GENUS 35. HYDRIANUM. Eabk. (1864.) 

 Cells as in Characium, but cell-contents at the beginning 

 homogenous, afterwards contracted into a dark green ovoid 

 corpuscle, from which, by oblique division, 2-4-8 biciliate zoo- 

 gonidia are produced, which escape by a terminal aperture. 

 Rabh. Alg. Eur. iii. 87. 



