326 Mr. J. Ralfs on the Nostochinee. 
Monormia*, Berkeley. 
Frond definite, gelatinous, elongated, linear, spirally curled and 
convoluted, inclosing a single continuous moniliform filament. 
Monormia is very closely allied to Trichormus, Allman, differ- 
ing principally, if not solely, im its definite linear frond, which 
incloses a single moniliform filament to be traced throughout all 
the peculiar convolutions of the frond. The vesicular cells are 
interstitial and occur singly. The sporangia are numerous, and 
are first formed from the cells at the greatest distance from the 
vesicular cells. 
Without due attention Monormia might easily be mistaken 
for a species of Nostoc, but the mass formed by its convoluted 
frond is not ineclosed by a common membranous pellicle as in 
that genus. 
Monormia intricata, Berk. Gleanings of British Alge, p. 46. t. 18 
(1832) ; Harvey, Man. of Brit. Algee, p. 185; ‘Phycologia Bri- 
tannica, t. 256 ; Hassall, Brit. Fresh. Alge, p. 286. £. 75. fig. 11. 
Nostoc intricatum, Meneghini, Mon. Nostoch. Ital. si 122 (1842). 
Anabena intricata, Kitzing, Phyeologia Germanica, p.171 (1845); 
Species Algarum, p. 288 ; Tabulee Phycologice, p. 50. t. 94. fig. 1 
In ditches of the marsh to the south of Frindsbury Canal, near 
Gravesend, Rev. M. J. Berkeley; in brackish ditches at Shirehampton, 
near Bristol, G. H. K. 7. ; near Wareham, Rev. W. Smith. Germany, 
Kiitzing. 
This species occurs m slightly brackish ditches as floating ge- 
latinous masses, each about as largé as a walnut, and usually of 
a reddish brown colour. When a small portion of the plant is 
examined with a lens of moderate power, it is seen to consist of 
an elongated continuous moniliform filament included im a de- 
finite linear gelatinous sheath, which is very much curled and 
convoluted, and the apposed surfaces of which are more or less 
coherent. The vesicular cells are somewhat oblong, and rather 
larger than the nearly spherical ordinary cells. The sporangia 
are numerous, twice the diameter of the ordinary cells, and per- 
fectly spherical. 
When the sporangia are mature the definite outline of the 
linear frond is almost lost, and then there is little to distinguish 
the plant from Trichormus but the peculiar convolutions of the 
moniliform filament. The original colour of the gelatinous frond 
has also then disappeared, and the plant has assumed a pale 
greenish tint. 
In drying, the plant stains paper of a deep blue or purplish 
colour. 
Parte VIIL. fig. 1. 
* By Mr. G. H. K. Thwaites. 
