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the branches are scarce. It differs from H. laminosus Hansg. in its 
habit, its branches, and other points. 
The branches are themselves often further branched, and towards 
their apices very often consist only of empty sheaths, the cells having 
escaped. 
Genus Stigonema A g. 
43. S. hormoides (Kutz.) Bornet et Flah. (Bevis. des Nostoc. 
Heterocyst., p. 69; Scytonema hormoides Kutz. ; Sirosiphon 
brevis Kutz., Botan. Zeit., 1847, p. 196 ; Tabulae Phycolog., 
ii. p. 10, t. 34, f. ii. ; Sir o siphon hormoides Kutz., Species 
Algar. p. 316 ; Tabulae phycolog., ii. p. 10, t. 34, f. iv. 
Crass, fil. 6 *5-8 *5 /a. 
Hab. Near Westport, Co. Galway, Ireland. 
This is the first time we have met with this species in the British 
Isles. 
Homocysteae. 
Order Vaginarie^e. 
Genus Schizothrix Ki'itz. 
44. S. cuspidata nob. ( Symploca cuspidata West, Alg. of 
W. Indies, Journ. Linn. Soc., xxx. (1894) p. 273, pi. xvi. 
figs. 1-7). 
This is certainly a Schizothrix, and evidently belongs to Gomont’s 
subgenus Symplocastrum. 
45. S. funalis sp. n. 
In strato molli tenui brunneo mixta cum Calothrice 
parietina , sine calce. Fila flexuosa inferne breviter trunciformia 
pseudoramosa ; pseudo-rami contorti et valde funiformes, 
apicem versus latiores. Vaginae firmae, amplae, lamellosae, in 
partibus inferioribus brunneo-nigrescentes, in partibus supe- 
rioribus lutescentes. Trichomata aeruginea parallela, 1-2 
(plerumque 2) in pseudo-ramis ; articuli diametro circiter duplo 
longiores. 
Crass, fil. 8-12 ; crass, trich. 0*5-0 *7 /x. 
Hab. Slieve Donard, Co. Down, Ireland. 
This probably comes nearest to S. lacustris A. Braun and 
S. Creswellii Harvey, but is characterised by its smaller size, its 
closely twisted threads, &c. 
Genus Microcoleus Desmaz. 
46. M. delicatulus sp. n. 
Fila variis algis consociatis, simplicia; vaginae mucosae, 
achroae, apice evanescentes. Trichomata subparallela sub- 
tortiave intra vaginam permulta ; articulis diametro paullo 
