NOSTOCHINE.E. 295 



ally spherical, of larger size and ciliated, at intervals. Fructi- 

 fication, large zoospores developed in the ordinary cells. — 

 Sph^eozyga, from the Greek sphaira, a sphere, and zygos, 

 a yoke. 



Sphserozyga Carmichaelii. Captain Carmichael's 

 Sphserozyga. 



Frond a thin, gelatinous skin, of a vivid green colour, 

 containing minute, straight or slightly curved, necklace- 

 like threads, which taper towards both ends. Zoospores 

 large, oblong, twice or thrice the length of their diameter. 



This plant grows on decaying algse, in the sea, or in 



brackish ditches. 



Sphaerozyga Thwaitesii. Thwaites's Sphsero- 

 zyga. 



Frond very gelatinous, of a dark green, sometimes almost 

 black colour, containing pale green, curved, entangled 

 threads ; connecting-cells large, somewhat oblong, ciliated, 

 of a pale colour, sometimes terminal ; ordinary cells some- 

 what flattened. Zoospores dark brown. 



Sphserozyga Broomei. Broome's Sphserozyga. 



Threads very slender ; connecting-cells smooth, some- 

 what square, rather longer than wide. Zoospores numer- 

 ous, elliptical, about twice the length of their diameter, and 

 only a little wider than the ordinary cells. 



This species was discovered by Mr. G. E. Broome, on 

 dead leaves of Myriophyllum, etc., in a brackish ditch 

 at Shirehampton, near Bristol. 



Sphserozyga Berkeleyana. The Rev. M. J. 

 Berkeley's Sphserozyga. 



Threads when young enclosed, one or several together, 



