Mr. J. Ralfs on the Nostochinez. 3831 
on one side and apparently an ordinary cell on the other, but 
this occurs only when the sporangia begin to be developed, and. 
the individual on one side is more forward than that on the 
other. In such a case close examination will detect a slight pre- 
liminary elongation of the incipient sporangium. The sporangia 
indeed are always developed, first on one side of the vesicular 
cell and then on the other, and whatever number may occur 
together they follow the same rule, and are produced alternately 
adjacent to those previously formed, and as they are thus pro- 
duced in succession they all vary in size (except in the mature 
plant), the inner ones in each group being the largest. 
Spherozyga differs from Trichormus and Dolichospermum by 
producing its sporangia adjacent to the vesicular cells ; its fila- 
ments also are straighter, and its sporangia more elongated than 
in the former genus. The interstitial position of the sporangia 
and vesicular cells distinguishes it from Cylindrospermum, and 
the ordinary cells are not disciform as in Spermosira. 
* Filaments moniliform ; sporangia elongated, not turgid. 
1. S. Carmichaelii (Harvey). Filaments moniliform, with tapering 
extremities ; ordinary joints distinct, subquadrate ; sporangia ob- 
long; vesicular cells spherical. Belonia torulosa, Carmichael, 
Alg. Appin ined. ; Harvey in Hooker’s Brit. Flora, vol. ii. p. 379 
(1833) ; Manual of Brit. Algee, p. 167. Spherozyga compacta, 
Kiitzing, Phycologia Generalis, p. 211 (1843); Phycologia Ger- 
manica, p.172. Anabena marina, De Brébisson in Ann. Se. Nat. !; 
Kiitzing, Species Algarum, p. 287; Tabule Phycologice, t. 92. 
fig. 111. Spherozyga Carmichaelii, Harvey, Phycologia Britan- 
nica, t. 113 A (1847) ; Kitzing, Species Algarum, p. 294 ; Tabulee 
Phycol. t. 99. fig. 4. 
B. tenuissima ( 
). Filaments very slender. 
On the damp soil in salt-marshes flooded at spring tides, more 
rarely in brackish ditches or upon decaying marine alge. Appin, 
Capt. Carmichael. Anglesea; Barmouth; Penman Pool near Dol- 
gelley ; Braunton near Barnstaple; Penzance, J. R. Shirehampton 
near Bristol, Mr. Thwaites. 
f. Shirehampton, Mr. Thwattes. 
France, Brébisson ; Germany, Kiitzing. 
Stratum tender, very thin, of a dark or bluish green colour 
when recent, but opake and glaucous when dry. Filaments short, 
straight, slender, moniliform, with attenuated ends. Ordinary 
joints distinct, the terminal ones longer than broad and trian- 
gular or conical, the others nearly equal in length and breadth, 
at first quadrate, finally rounded at their angles, and when dried 
orbicular. Whilst dividing they are geminate and longer than 
broad. Vesicular cells orbicular or oval and generally ciliated. 
